Turkey summoned the Israeli ambassador to the foreign ministry to discuss the incident, which heightened tensions between Turkey and Israel to new levels.

It was also reported that Turkey warned Israel against "unprecedented and incomprehensible ramifications."

Two TV networks reported earlier that Israeli warships attacked the six ships carrying pro-Palestinian activists and aid for blockaded Gaza, killing at least 20 and wounding more that 50 people.

"We were not expecting such an operation in international waters," Omer Faruk Korkmaz, an official of the pro-Islamic aid group, IHH, that led the aid shipment, said in Turkey. "Israel has been caught red-handed and the international community will not forgive it."

The al-Jazeera network reported that senior Turkish officials were expected to convene an emergency meeting to discuss their stand regarding what they referred to as "the Israli attack on the freedom sail."

The Turkish protest against Israel began on Sunday evening, as hundreds of protestors gathered outside the Israeli Embassy in Ankara and the Israeli Consulate in Istanbul in order to protest "the Israeli acts of provocation against the sail."

On Sunday evening, Turkish Prime Minister Recep Tayyip Erdogan rejected Israeli claims about the Turkish link to the sail. He said the boats, carrying aid to the Gaza Strip, had nothing to do with the Turkish government.

"It's an international civilian act," he said during a visit to Brazil. "This step has only been taken for humanitarian purposes. I think there will be no problem if Israel shows a humanitarian stance towards the humanitarian aid."