A trial began in Turkey on Tuesday against four Israeli military commanders accused of leading a raid on the high seas against a Gaza-bound aid ship - a raid that resulted in the death of nine activists.
Hundreds of protesters chanting anti-Israeli slogans gathered outside Istanbul's main courthouse as the trial opened.
"People from every nation and every religion with a conscience are here to hold Israel accountable for 1,000 years-old history," one woman said. "May God help us succeed in our case."
With citizens from 37 countries due to participate in the trial, but not the Israeli commanders, the Turkish media is describing it as the world's largest international trial. Israel has dismissed the proceedings as politically motivated, calling it a "show trial."
The boat Mavi Marmara was leading an international flotilla of ships carrying pro-Palestinian activists seeking to break Israel's economic blockade of the Gaza Strip, when it was intercepted by Israeli forces in May 2010.
Israel claims its forces acted in self-defense. But Turkish prosecutors are demanding life sentences for four of Israel's most senior retired commanders, including the former head of the army.
Turkish-Israeli relations have collapsed since the raid. Semih Idiz, a writer for the Turkish newspaper Milliyet, warned the case can still further strain relations.
"Any court situation that provides a platform for what Israel sees as enemies of Israel is not welcome," he said. "Turkey is not a negligible country in this part of the world. And to have a Turkish court highlighting Israeli crimes, quote unquote, is not a comfortable thing and this court is attracting a lot of attention in the Middle East. So there is a gallery for Turkey in going through this and that is what is bothering Israel."
Observers said there is widespread anger in Turkey at Israel over the deaths, in particular among the grassroots supporters of the prime minister's Islamic rooted party. Turkish presidential elections are expected in 2014.
International relations expert Cengiz Aktar of Bahcesehir University said "with such a nationalist and actually nationalist rhetoric, the prime minister of Turkey will never dare, for a second, [to] re-establish relations and especially now right before the Israeli elections in January. I think he has made out of the anti-Israeli policy a permanent agenda item out of his future presidency. So he will want yield on that."
The trial is predicted to further hamper efforts - in particular by Washington - to rebuild relations between its two key allies in the region.
Israeli Prime Minister Benjamin Netanyahu's government has made recent overtures to Turkey, indicating it maybe moving closer to Ankara's demands for an apology and compensation to families of those killed.
But last month, Turkish Prime Minister Recep Tayyip Erdogan repeated his demand for Israel to end its embargo against Gaza in return for a normalization of relations.
Diplomatic columnist Idiz said Ankara has little interest in a rapprochement.
"There is an asymmetrical situation here. Netanyahu needs improved relations and Erdogan doesn't, and he can't really afford to be aiming for improved relations when the public has not felt there is enough atonement on Israel's side for the killings," he said.
Ankara is expected to pursue the extradition of the commanders through Interpol, but observers say such attempts are unlikely to succeed and will only further worsen tensions between the countries.