Turkey is commemorating the first anniversary of Israeli forces' attack on an aid flotilla headed to Gaza that left nine pro-Palestinian activists dead. The deaths - eight Turkish citizens and an American citizen of Turkish descent - have ruptured relations between once close allies.
The crowd chanted "Damnation to Israel," as they marched through the center of Istanbul to remember the nine people killed by Israel's security forces while on the Turkish ship the Mavi Marmara. The international flotilla last year hoped to break the Israeli economic blockade of Palestinians living on the Gaza Strip.
Those marching on the one-year anniversary are still angry over the killings.
PERSON1: "There was blood, violence and tears on Mavi Marmara, and we are still feeling that pain. We lost our nine brothers, and Israel is responsible for this."
PERSON2: "They killed our brothers on [the] Marmara ship and in Palestine. [They] always kill our brothers, and we protest Israel, and we say that Israelis [are] terrorists."
Since the incident, the two nations continue to exchange angry barbs over who was responsible for the deaths on the Turkish flagship.
The flotilla's organizers - the Free Gaza Movement and the Foundation for Human Rights, Freedoms and Humanitarian Relief (IHH), a Turkish aid group - have been planning an even larger event this year, reportedly with a 15-vessel flotilla with more than 1,000 international activists on board.
IHH deputy chief Huseyin Oruc says the international controversy about last year's killings offers protection to the ship.
"Now the whole world knows that this mission is a peaceful mission," said Oruc. "Any international committee can come to check the boats. And this is the only way to defend the boats. Now the whole world will watch the boats will follow the boat, and Israel will not make the same mistake again."
Israel accuses the IHH of being more a political organization than a charity, claiming it has close links to Hamas, which the European Union and the U.S. consider a terrorist organization, a charge the charity denies.
But in an attempt to dispel such criticisms, this year's flotilla is more broadly supported by organizations around the world. A total of 15 countries, mainly from Europe, are providing ships. The organizers claim such support will stop Israel from military intervention.
But Dror Feilier, spokesman for the Swedish ship, says they are still preparing for the worse.
"It will be passive resistance, in Sweden, and in other countries, we are going to train all the passengers in non-violent resistance, we are not giving the boats away," said Feilier.
But Israel continues to defend its actions and warns it will continue to enforce its economic embargo. The possibility of another showdown has led the United States to lobby Ankara to stop the flotilla.
But Turkish Foreign Minister Ahmet Davutoglu ruled out any intervention.
It should be known that Turkey will give the necessary response to any repeated act of provocation by Israel on the high seas, he said. Davutoglu added that those who believe Turkey should take certain steps to stop the new flotilla must first warn Israel not to repeat the human tragedy it caused last year.
Turkey's ruling AK party's tough stance towards Israel and, in particular, its support of the flotilla, does play well with the country's large religious population, according to political scientist Nuray Mert of Istanbul University. She says with the country in the midst of a general election, that could be a key factor in government policy.
"There are these speculations that, well, it's part of the election campaign," said Mert. "It may be an effort to renew the popularity and renew the enthusiasm that they had the last year. It's a popular cause, and it will work for the present governing party."
Turkish voters go to the polls on June 12. With the flotilla due to set sail sometime in the last week of June, observers say time is running out to avoid the risk of another high seas confrontation.