At least 10 people were killed on Monday when Israeli naval commandos boarded aid ships bound for the Gaza Strip, meeting resistance from pro-Palestinian activists, Israel's Channel 10 television said.
The six-ship convoy carrying aid for Palestinians and led by a Turkish vessel with 700 people on board set sail for Gaza from international waters off Cyprus on Sunday in defiance of an Israeli-led blockade of the territory.
It was not clear whether the clashes were taking place on just one of the six boats making up the aid convoy, and the Israeli army had no immediate comment on the incident.
Shortly afterwards, the Israeli military censor ordered a block on all information regarding those injured or killed during the storming of the ship.
Turkey's CNBC-e agency reported reported that theTurkish Foreign Minister Ahmet Davutoglu plans to call a meeting of the United Nations Security Council to discuss the Israeli raid on a convoy of aid ships.
Davutoglu is going to New York to summon the meeting, the channel said, without saying how it got the information. Turkey holds a temporary seat on the council.
Turkey's foreign ministry earlier warned that the raid on the flotilla, which included Turkish vessels, may lead to "irreparable consequences" in bilateral ties.
"This deplorable incident, which took place in open seas and constitutes a fragrant breach of international law, may lead to irreparable consequences in our bilateral relations," it said in a statement.
The Israeli ambassador, earlier, was summoned to the Turkish foreign ministry, a Turkish diplomat said.
"The ambassador (Gabby Levy) was summoned to the foreign ministry. We will convey our reaction in the strongest terms," the diplomat, who asked not to be named, told AFP.
Deputy Prime Minister Bulent Arinc meanwhile conveyed an emergency meeting with senior officials, including the minister of the interior, the navy chief and the army's head of operations, Anatolia news agency reported.
Arinc was in charge as Prime Minister Recep Tayyip Erdogan is currently on a visit to Chile.
Police stepped up security outside the residence of the Israeli ambassador, where several dozen protestors gathered to protest the Israeli operation against the aid flotilla, television footage showed.
A group of protestors gathered also outside the Israeli consulate in Istanbul, waving Palestinian flags, Anatolia said.
Arabs urged to "rise up"
The Islamist Hamas movement, meanwhile, urged Arabs and Muslims to "rise up" in front of Israeli embassies across the globe in protest against Israel's deadly raid.
Palestinian President Mahmoud Abbas slammed as "a massacre" the deadly Israeli raid and urged an immediate meeting for the Arab League.
"What Israel has committed on board the Freedom Flotilla was a massacre," Abbas was quoted as saying by the official Wafa news agency.
Arab League Chief Amr Moussa condemned the attack and described it as a "crime" against the innocent activists and called for an immediate meeting on June 1.
"We condemn this crime, taken against a humanitarian mission and people. They were trying to help people. They were not on a military mission. Everyone should condemn this," Moussa told AFP.
"We are now conducting calls to Arabs to decide on our next step," said Moussa, who heads the 22-country organization based in Cairo.
Media reports also suggested that senior Arab Israeli Islamist leader Sheikh Raed Salah, who heads the northern branch of the Islamic Movement in Israel, had been injured during the pre-dawn raid which took place in international waters off Israel.
We condemn this crime, taken against a humanitarian mission and people. They were trying to help people. They were not on a military mission. Everyone should condemn this
Arab League Chief Amr Moussa
In Europe, condemnation was equally swift.
France said that "nothing can justify" the violence of Israel's Gaza ship raid, while German Foreign Minister Guido Westerwelle said he was "deeply concerned" about the deaths.
The European Union demanded Israel mount a "full inquiry" into the killing of at least 10 people in a raid on a flotilla of aid ships bound for Gaza.
EU foreign affairs chief Catherine Ashton warned that Israel's "continued policy of closure is unacceptable and politically counterproductive," demanding "an immediate, sustained and unconditional opening" of crossings to Gaza.
Greece withdrew from joint military exercises with Israel in protest at the raid, as it summoned Israel's ambassador to demand an "immediate" report on the safety of about 30 Greeks on board the flotilla.
The bloody ending to the high-profile mission to deliver supplies to Gaza came on the eve of a meeting in Washington between President Barack Obama and Israeli Prime Minister Benjamin Netanyahu.
According to Israel's private channel 10 television, Israeli marine commandos opened fire after being attacked with axes and knives by a number of the passengers on board the aid ships, the television said, without giving the source of its information.
The convoy, led by a Turkish vessel with 700 people on board, including 1976 Nobel Peace Prize laureate Mairead Corrigan Maguire of Northern Ireland, European legislators and an elderly Holocaust survivor, set off in international waters off Cyprus on Sunday in defiance of an Israeli-led blockade of the Gaza Strip and warnings that it would be intercepted.
The flotilla was organized by pro-Palestinian groups and a Turkish human rights organization. Turkey had urged Israel to allow it safe passage and said the 10,000 tons of aid the convoy was carrying was humanitarian.
Israel had said it would prevent the convoy from reaching the Gaza Strip, which is run by the Islamist Hamas group.
Attempting to draw attention
The flotilla, which includes three cargo ships and three passenger ships, is trying to draw attention to Israel's three-year blockade of the Gaza Strip. The boats are carrying items that Israel bars from reaching Gaza, like cement and other building materials. The activists said they also were carrying hundreds of electric-powered wheelchairs, prefabricated homes and water purifiers.
This is the ninth time that the Free Gaza movement has tried to ship in humanitarian aid to Gaza since August 2008.
Israel has let ships through five times, but has blocked them from entering Gaza waters since a three-week military offensive against Gaza's Hamas rulers in January 2009. The flotilla bound for Gaza is the largest to date.
Israel imposed the blockade on Gaza after Hamas militants violently seized control of the seaside territory in June 2007.
Israel says the measures are needed to prevent Hamas, which has fired thousands of rockets at Israel, from building up its arsenal. But U.N. officials and international aid groups say the blockade has been counterproductive, failing to weaken the Islamist group while devastating the local economy.