The Legality of Israel’s Naval Blockade of Gaza


By Katherine Iliopoulos

A flurry of debate – political and legal – has followed in the days since Israel’s deadly raid on a Gaza-bound aid flotilla that resulted in the deaths of nine activists. Israel has been accused of breaching international and human rights law and in turn, has invoked international law to defend the actions of its naval forces.

The facts surrounding the actual incident on board one of the ships remain unclear, with both sides pointing the finger at the other for initiating the violence. What can be examined however at this early stage is the question whether the blockade itself is lawful and the nature of Israel’s obligations under international law.

In peacetime, according to the Law of the Sea, a ship on the high seas may be stopped only either with the permission of the flag state, or if it is suspected of committing international legal offences such as piracy or slave trading. But it is widely agreed that Israel’s action took place as part of an armed conflict. Israel has been engaged in an armed conflict in the Gaza strip with Hamas, a non-state entity, for some time. And Israel’s maritime blockade that is in effect off the coast of Gaza has been implemented in connection with this ongoing armed conflict. The law of armed conflict thus applies.

The Legality of the Blockade

Under the law of armed conflict, hostile actions by naval forces may be conducted across any maritime zone, including the high seas (international waters). Thus, the fact that the Gaza flotilla was intercepted on the high seas does not necessarily make it unlawful. A blockade is a recognised – that is, lawful – method of warfare, just like espionage or the use of camouflage are lawful methods of war. According to the San Remo Manual of International Law Applicable to Armed Conflicts at Sea, a naval or maritime blockage consists of “the blocking of the approach to the enemy coast, or a part of it, for the purpose of preventing ingress and egress of vessels or aircraft of all States.” And Article 42 of the UN Charter lists a blockade as an action to which the UN Security Council may have recourse in order to give effect to its decisions.

The legality of a blockade turns on several cumulative conditions, which have been invoked by Israel to justify its actions: proper declaration and notification, maintaining an effective blockade, applying the blockade impartially, not preventing access to the ports of States not involved in the conflict and finally, facilitating humanitarian passage. Israel claims that its enforcement of the blockade satisfied all these conditions, and that the blockade is therefore lawful.

A lawful blockade entails the right to stop all merchant vessels seeking to enter the blockaded area. If a ship is carrying “absolute contraband” – that is, weapons or munitions – those items can be seized. If it is carrying other contraband, the state wishing to seize particular items must have given notice by publishing the relevant lists in advance. Documents obtained by the Israeli human rights group Gisha have revealed that chocolate, potato chips, fresh meat and fishing rods are considered contraband and may not enter Gaza. According to Israel, the entry of goods into the Gaza Strip is now limited to a “humanitarian minimum” which includes only those goods that are considered “essential to the survival of the civilian population.”

Reports indicate that the ships were carrying civilians and humanitarian relief supplies. Such vessels can be lawfully stopped and searched. A neutral ship can be attacked and sunk if it attempts to cross the blockade line and resists arrest or an order to stop, but an attack would be unlawful if the injury to the civilians on board was expected to be “excessive.” This is not to say however that the Israeli action constituted an “attack” on the vessel, but it does appear that some civilians on board the ship were attacked (see discussion below).

The incident has sparked a debate among legal commentators as to whether a blockade can be lawfully instituted against a non-state group, because they say that an international armed conflict – that is, one being waged between two states – is a prerequisite to a lawful blockade.

Professor Kevin Jon Heller suggests that the conflict is non-international, rendering the blockade unlawful because there seems to be little, if any, state practice to support the idea that a blockade is legally permissible in a non-international armed conflict.

The complexity of the armed conflict between Israel and Hamas means it is not easy to characterise. Yet, due to the absence of any clear prohibition of blockades in non-international armed conflicts, there does seem to be a reasonable case for believing that the use of a blockade is not inherently forbidden by international law in this case.

Humanitarian Relief and a State of Occupation

During a state of occupation, relief consignments must be permitted to cross blockade lines, subject of course to being searched, verified and supervised. There is a strong argument to suggest that Israel is an Occupying Power in the Gaza Strip, although it refuses to accept such a characterisation. Indeed, the situation with respect to the status of Gaza in this sense remains unclear.

The Fourth Geneva Convention seems to apply in the Gaza Strip because although Israel withdrew its military forces and settlers from the territory in 2005, it still exercises control over Gaza’s airspace, sea space and land borders, and over its electricity, water, sewage and telecommunications networks and population registry. Thus, it could be said to be maintaining effective control over the territory.

A state of occupation alters the legal landscape, bringing with it a different set of obligations.
Israel has been criticised for failing to meet its obligations as occupier, which entail providing for the general welfare of the inhabitants by ensuring their access to basics such as adequate food, water, shelter and medical facilities. More specifically, in this case, Israel has been accused of breaching another of its obligations as occupier by refusing to allow the relief consignment to cross the blockade line.

While customary international law requires belligerent parties to allow relief operations to take place, they can refuse in certain situations– but not on arbitrary grounds. The IDF has claimed that it did not refuse the passage of humanitarian aid per se; rather, it declared that it would allow the entry of the humanitarian consignment that was on board the ships into Gaza via the Israeli port of Ashdod, and not via the blockaded area. A belligerent such as Israel is well within its rights to take steps to control the content and delivery of humanitarian aid, so as to ensure that consignments do not include weapons. Obviously this entails the right to stop and search (as mentioned earlier): a right that remains in place whether there is a state of occupation or not.

The Incident on Board: Proportional and Necessary?

Assuming the blockade is lawful, Israel was within its rights to stop the flotilla and search its contents. What remains hotly disputed is the manner in which Israeli forces tried to enforce the blockade. The enforcement of a blockade must be lawful: that is, the measures taken need to be necessary and proportionate.

The question of proportionality is relevant to a consideration of the actions of Israeli armed forces in relation to what occurred on board the Marvi Marmara. There have been various media reports that have presented competing versions of the incident, but the precise facts remain uncertain. Each side has accused the other of initiating the violence, and of invoking their respective rights to self-defence.

Sarah Colborne, director of campaigns and operations at the Palestine Solidarity Campaign, was on board the Mavi Marmara. She told The Telegraph of seeing an injured person being brought to the back of the deck being treated by a doctor and a first aid officer. “He was shot in the head. It was clear it was not some paint ball. It was a bullet,” she said. “We had no weapons. We were on a peaceful humanitarian mission.”

Upon her return to Turkey, activist Nilufer Cetin said Israeli troops opened fire before boarding the Mavi Marmara, the scene of all nine fatalities. The official Israeli version is that armed force was used only after its boarding party was attacked, that its troops only opened fire in self-defence after being attacked by activists wielding metal bars and knives.

An Unlawful Blockade?

If the blockade is considered unlawful however, its enforcement – no matter how it is conducted – is unlawful. Israel seems to have satisfied the first four conditions of a lawful blockade. What may render its blockade unlawful however, is its interdiction of humanitarian vessels over a long period of time.

Over time, an otherwise legal, effective blockade – such as the one in relation to Gaza – can resemble a siege in precipitating the starvation of civilians, which is prohibited as a means of warfare by Article 54 of Additional Protocol I and which, according to the Eritrea-Ethiopia Claims Commission, has formed part of customary international law since at least 1999. There is an argument to suggest that such a blockade could eventually come to be considered unlawful.

The sustained blockade that has been enforced in and around the Gaza Strip has had significant repercussions for the people of Gaza. They have been deprived of adequate supplies of essentials such as food and fuel. The United Nations Relief and Works Agency (UNRWA) says that a large proportion of families lack the means to purchase even the most basic items, including food, soap, school materials and clean drinking water. According to Amnesty International, the overall blockade on Gaza has led to mass unemployment, extreme poverty and food price rises caused by shortages. Eighty percent of the population remains dependent on humanitarian aid, but the UN says that as a result of the blockade, only one quarter of the necessary aid is able to reach those who need it.

There seems to be a strong argument in favour of the thesis that the Gaza blockade is in fact illegal because of its disproportionate effect on the population of Gaza.

One of the strongest arguments supporting the notion that the blockade is illegal is that – by banning most items except for the most essential for survival – it is in fact an economic sanction and a form of collective punishment, which is prohibited by Article 33 of the Fourth Geneva Convention. According to a report published in May by the UN Development Programme (UNDP), Israel’s blockade remains the “major obstacle” to reconstruction and any realistic prospect for economic recovery or development. On its face, the blockade was instituted by to put pressure on Hamas to return captured Israeli soldier Gilad Shalit, to weaken what it considers to be a terrorist organisation and to put an end to rocket attacks. But there is evidence that suggests that these economic and other measures have been taken to punish the people of Gaza for supporting Hamas.

This argument is supported by UN High Commissioner for Human Rights Navi Pillay, who stated that Israel’s embargo was illegal. “International humanitarian law prohibits starvation of civilians as a method of warfare and it is also prohibited to impose collective punishment on civilians,” she said. Her remarks coincided with Israel’s detention of yet another ship on 5 June, the Rachel Corrie, which was carrying medical supplies and construction materials.

The International Response

On 1 June, the UN Security Council adopted a non-binding presidential statement denouncing the sustained blockade that is impeding the flow of goods and people to Gaza as well as the distribution of humanitarian assistance. It called for “a prompt, impartial, credible and transparent investigation [into the incident] conforming to international standards.”

As part of such an inquiry, one question that may be asked is whether those who ordered or participated in the attack could be brought before the International Criminal Court.

Professor William Schabas said on 1 June that since the Mavi Marmara was a Turkish ship, Turkey has the power to exercise jurisdiction over the alleged crimes that were committed on board. And by the same token, Turkey – who is not a State Party – could assign jurisdiction to the ICC by virtue of the same provision of the Rome Statute that was invoked by the Palestinian Authority in 2009. Article 12(3) provides that a non-State Party can ‘accept’ the jurisdiction of the Court over crimes committed on its territory, or in this case, a vessel bearing its flag. Two possible crimes that could form the basis of a prosecution can be found in Article 8(2)(b) of the Statute: (i) Intentionally directing attacks against the civilian population as such or against individual civilians not taking direct part in hostilities; and (ii) Intentionally directing attacks against civilian objects, that is, objects which are not military objectives.

More information on what exactly happened on board the Mavi Marmara, and whether it was lawful, is sure to follow in the next days and weeks. It is certain however that the incident highlighted the devastating effects of the blockade on the people of Gaza. UN Secretary-General Ban Ki Moon said the underlying problem behind the events of 31 May was the sustained, crippling Israeli siege of Gaza which he described as a “counter-productive and unsustainable” measure that must be lifted immediately.

Katherine Iliopoulos is an international lawyer based in The Hague, Netherlands.

Related Links:

The Gaza Flotilla and the maritime blockade of Gaza: Legal Background
Israel Ministry of Foreign Affairs
May 31, 2010

Interception of the Gaza Flotilla: Legal Aspects (PDF)
Israel Defence Force Advocate General

UN Security Council Statement on Gaza Flotilla
United Nations
June 1, 2010

Gaza Flotilla: Can Israel be Brought to the ICC?
By William Schabas
June 1, 2010

Suffocating Gaza: The Israeli Blockade’s Effect on Civilians
Amnesty International
June 1, 2010

Restrictions on Passage of Goods into and out of Gaza
Gisha: Legal Center for Freedom of Movement

Gaza Flotilla Attack: British activists tell of abuse by Israelis
By Justin Vela
The Telegraph, June 3, 2010

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  3. Blockade as an Act of War
  4. Israel Defends Troop Conduct in Gaza; Snubs UN Inquiry
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