Israel has been accused of "kidnapping" a ship crewed by international activists when it detained them in an early morning raid on Monday.
The ship, dubbed the Madleen, was carrying aid for the people of Gaza, including baby formula and food.
The Freedom Flotilla Coalition, which organised the ship, claimed the activists, which included climate protester Greta Thunberg, were detained while sailing through international waters.
Israel says the action was a necessary action to enforce the naval blockade of the territory it maintains.
Here's a look at the legal debate.
What happened?
Here's a quick recap of the Madleen's journey.
The Freedom Flotilla Coalition boat set sail from Italy on June 1 in an attempt to break Israel's blockade of Gaza and deliver aid to the territory by sailing to Gaza's shores in defiance of Israeli control.
The ship was intercepted by Israeli forces early Monday, and the crew was taken to Israel.
Israeli media reported the ship docked in Ashdod Port, about halfway between the Gaza Strip and Israel's major population centre of Tel Aviv, almost 18 hours after it was seized.
Israel's foreign ministry said the Madleen's passengers underwent medical examinations "to ensure they are in good health" after they made landing.
A statement released by the foreign ministry later said all of the Madleen's crew members had been taken to Ben Gurion Airport to "depart Israel and return to their home countries".
What are international waters?
According to international law, countries can claim some area of sea as their own territory — anything up to 12 nautical miles (19 kilometres) from their own coastlines.
Ships and their crews are subject to a nation's laws when sailing in its territorial seas.
When ships go beyond those areas, they reach international waters — also known as the high seas — and are no longer under any nation's jurisdiction.
That doesn't mean the high seas are lawless, though.
These neutral areas are regulated by the UN Convention on the Law of the Sea, and are open to use by all countries for legitimate activities.
It means nations generally don't have the right to seize ships in international waters, but there are some exceptions, including if there are suspicions of piracy or during armed conflict.
The Freedom Flotilla Coalition has claimed the Madleen was in international waters, about 200 kilometres off the coast of Gaza, when Israel intercepted the boat.
Exactly where the ship was stopped could not be independently verified, and Israeli authorities have not disclosed the location, though they did not dispute the FFC's characterisation of the location.
Why do critics say Israel acted unlawfully?
The Freedom Flotilla Coalition argues Israel had no right to take the crew to land because the ship hadn't entered the nation's territory and posed no military threat.
"We're basically talking about people who were sailing in the international waters, and then Israel basically captured them and abducted them into Israel," Freedom Flotilla lawyer Hadeel Abu Salih said.
"The situation we're talking about now is a situation that Israel brought those people inside of Israel, and now they want to deport them based on the claims that they entered Israel illegally."
What does Israel say?
Israel hasn't disputed the Freedom Flotilla Coalition's claim that the Madleen was intercepted in international waters.
Its justification for stopping the boat hinges around an exception to the maritime law, which would allow some "militarily justified" actions.
Essentially, Israel says it was defending a legitimate naval blockade of Gaza and was responding to the Freedom Flotilla's stated intention to breach it.
"The maritime zone off the coast of Gaza is closed to unauthorized vessels under a legal naval blockade, consistent with international law," the Israeli foreign ministry said in a statement released before the Madleen was intercepted.
"The Gaza maritime zone remains an active conflict area, and Hamas has previously exploited sea routes for terrorist attacks, including the October 7th massacre.
"Unauthorized attempts to breach the blockade are dangerous, unlawful, and undermine ongoing humanitarian efforts."
Former Israel Defense Forces (IDF) senior lawyer Eran Shamir-Borer argued Israel was acting lawfully in defending its blockade of Gaza.
"Once a naval blockade has been imposed there is a right, even an obligation, to enforce it," he told the ABC on Tuesday.
"Enforcing could be done not just with respect to an actual breach of such a blockade, but also if it is an attempted breach.
"An attempted breach could be decided by way of the intention, declared intentions, stated intentions of those involved in the flotilla, those on board the vessel, and then you could just enforce this also on the high seas, actually from the moment when they have made their intentions clear that they want to breach a lawful naval blockade."
Is the blockade legal?
Israel's justification for intercepting the Madleen relies on its naval blockade also being considered legal.
Douglas Guilfoyle, a professor of international law and security at UNSW, said it would be illegal for a nation to attempt to enforce an illegal blockade.
A United Nations inquiry in 2011 found Israel was allowed to impose the measure to protect its security but experts and humanitarian organisations argue the nature of the blockade has changed.
According to the San Remo Manual on International Law Applicable to Armed Conflicts at Sea, which sets out customary international law on naval conflicts, a blockade may be used during conflicts if:
- It is formally declared and publicly notified
- It is effectively enforced in practice
- It is applied impartially to all ships
- It does not block access to neutral ports or coastlines
- It does not stop the delivery of humanitarian aid to civilians
While Dr Guilfoyle said the point at which any given blockade becomes illegal is contentious, it was his opinion it was "clear cut" Israel's was no longer lawful.
"In my view, the primary purpose of the blockade became starvation of the civilian population, at the latest, when the government of Israel declared on March 2 that it was halting all entry of all goods and supplies to Gaza until Hamas resumed negotiations and releasing hostages," he said.
"From this time, there has been a declared government policy of using starvation as a weapon of war that makes the blockade illegal until adequate supplies enter Gaza."
Amnesty International says Israel has an obligation to ensure Palestinians have enough access to humanitarian supplies.
Amnesty and other groups see the seizure of the Madleen as part of a campaign by Israel to limit or entirely deny aid in Gaza.
Israel's aid policy during the war has driven the territory toward famine, the International Criminal Court (ICC) has alleged.
Prime Minister Benjamin Netanyahu is accused by the ICC of using starvation as a method of warfare by restricting humanitarian aid into Gaza, charges he has rejected.
Israel argues it has allowed enough aid to enter Gaza and instead accuses Hamas of siphoning it off.
What happens if laws were broken?
Dr Guilfoyle said it was up to individual members of the United Nations to call out illegal acts as they see them.
"International law is a system without central enforcement," he said.
"There is not always an international court capable of hearing a particular case."
He said with regards to the ongoing conflict, the International Criminal Court's jurisdiction only extends to events occurring in the Palestinian territories.
"While the international Tribunal for the Law of the Sea has ruled on similar cases, it only binds parties to the UN Convention on the Law of the Sea, and Israel is not a member of that convention," Dr Guilfoyle added.
What was on the Madleen?
The ship was manned by a crew of 12 volunteers, including a politician, a journalist, and high-profile activists.
Here are their names and home countries:
- Baptiste Andre, France
- Greta Thunberg, Sweden
- Suayb Ordu, Turkey
- Mark van Rennes, Netherlands
- Omar Faiad, France
- Pascal Maurieras, France
- Reva Viard, France
- Rima Hassan, France
- Sergio Toribio, Spain
- Thiago Ávila, Brazil
- Yanis Mhamdi, France
- Yasemin Acar, Germany
Rima Hassan, a French-Palestinian woman, serves as a member of European Parliament for France, while Omar Faiad is a journalist with Al Jazeera Mubasher.
ABC/AP
