JERUSALEM (AFP) – "We have sent a letter via the Turkish ambassador inviting all Turkish passengers or crew to come and give evidence in Israel," Tirkel Commission spokesman Ofer Lefler told AFP. He said the captain of the Mavi Marmara, on which nine Turkish activists were killed when Israeli forces stormed the ferry in international waters, had not yet responded to an invitation to testify that was sent on September 12. The deadly violence took place on the ferry, which was part of a six-ship aid flotilla trying to run Israel's blockade on the Gaza Strip. At the time of the operation, there were more than 600 people on the ferry. Israel says its commandos resorted to force only after they were attacked when they rappelled onto the deck of the ferry, but pro-Palestinian activists on board say the soldiers opened fire as soon as they landed. The four-man Israeli commission's investigation is limited to looking into the legality of the raid on the flotilla and of the Jewish state's actions to implement its naval blockade on the Hamas-ruled Palestinian enclave. The findings of the commission, whose work is being monitored by two foreign observers, is to be submitted to the United Nations. The commission does not have the authority to summon troops involved in the operation, but Lefler said on Thursday that armed forces chief Gabi Ashkenazi has been asked to testify for a second time before the panel on October 24. Ashkenazi appeared before the commission in mid-August when he defended his troops' use of lethal fire when they stormed the vessel. Turkey's ties with Israel, previously a close regional ally, have deteriorated amid vehement criticism from Ankara of the Jewish state's heavy-handed policies against the Palestinians. Relations nosedived after the Mavi Marmara raid.