In what Israel called “political theater” and a “show trial,” Turkey put four senior former Israeli military commanders on trial in absentia on Tuesday, for IDF action on the Gaza-bound ship Mavi Marmara in May 2010.

Nine pro-Palestinian activists — eight Turks and a Turkish-American — were killed in that incident aboard the vessel, which was part of an international flotilla trying to break the Gaza blockade. Israeli naval commandos commandeered the vessel and were attacked by activists.

Hundreds of people carrying Turkish and Palestinian flags gathered outside an Istanbul criminal court, where testimony from passengers who were on the Gaza-bound ship at the time of the IDF raid, as well as relatives of those who were killed, was to be heard.

A Turkish state prosecutor is seeking multiple life sentences for former chief of General Staff Gabi Ashkenazi, former OC Navy Eliezer Marom, former OC Air Force Amos Yadlin and former head of Air Force intelligence Avishay Levi. The prosecutor wants prison sentences of more than 18,000 years for each of them for their roles in the incident.

“The trial will look into what the commanders did, what crimes were committed aboard the ship. There may also be additional indictments along the way,” said Gulden Sonmez, a spokeswoman for IHH, an Islamic aid group that operated the Mavi Marmara.

Sonmez said Israel would be required to give up the defendants if they are convicted, and that other countries would be required to do the same if they are caught elsewhere in the world. Israel scoffed at that assertion, describing the Turkish trial as a “kangaroo court” aimed at stoking anti-Israeli propaganda.

“The so-called accused were not even informed or served or notified that they were going to be charged, which makes this one big puppet show,” said Yigal Palmor, spokesman for Israel’s Foreign Ministry.

Turkey has demanded a formal apology, compensation for victims and the families of the dead, and for the Gaza blockade to be lifted. The case symbolizes the rupture between Turkey and Israel, former allies whose diplomatic ties are effectively frozen. Israel has rebuffed Turkish demands to apologize for the raid on the ship and to compensate those killed as a precondition for normalizing relations.

Israel — stressing that its solders were attacked with clubs and poles by violent thugs aboard the vessel, and insisting that its blockade against Gaza, which is run by the terror group Hamas, is legal — has said it “regretted” the loss of life, rather than issuing a full apology, and has offered to pay into what it called a “humanitarian fund” through which casualties and relatives could be compensated.

Turkey disputes Israeli assertions that its soldiers acted in self-defense after being attacked by activists when they boarded the ship. The commando operation sparked condemnation worldwide and led to an easing of Israel’s blockade on the coastal territory.

A UN report into the Mavi Marmara incident released in 2011 concluded that Israel had used unreasonable force in stopping the Mavi Marmara, but that the blockade on Gaza was legal.