Syrian opposition groups are to meet in a bid to settle their differences, as the violence in their country threatens to descend into civil war, sources among the groups said Thursday.

An earthquake of 5.5 magnitude jolted southeastern Turkey Thursday, Turkey's quake observatory said, knocking the minaret off a mosque in the city of Sirnak but injuring no-one, officials said.

The tremor shook the southeastern province of Sirnak at 0552 GMT, 5.4 kilometers (3.3 miles) below the ground, Istanbul-based Kandilli Observatory announced on its website.

Around 2,500 Syrians have fled to Turkey in the last 48 hours, a Turkish foreign ministry official said Wednesday, saying the numbers had increased amid fresh attacks even targeting U.N. observers.

The number of Syrian refugees in camps set up in southeastern Turkey had reached 29,500, said the official who wished to remain anonymous. Some 1,500 Syrians had arrived in the last 24 hours, he noted.

Israel's state watchdog on Wednesday sharply criticized Israeli Prime Minister Benjamin Netanyahu over his handling of a 2010 military raid on a Gaza-bound flotilla which left nine Turkish nationals dead.

"In the process of decision making, which was led by the prime minister and under his responsibility, regarding the handling of the (flotilla), there were significant shortcomings," said a report published by State Comptroller Micha Lindenstrauss.

Istanbul police shot dead one of the two gunmen who opened fire with automatic weapons and threw a grenade at a police station late Tuesday, Anatolia news agency reported.

The two unidentified assailants attacked the police station at Istinye on the European shore of Istanbul and a police officer returned fire, killing one of them, Anatolia said.

Turkish Prime Minister Recep Tayyip Erdogan said on Tuesday that Kurdish would be taught in public schools, "a historic step" for Turkey.

"Our pupils ... will now be able to learn Kurdish as optional courses if there is a sufficient number (of students)," Erdogan told his ruling party members in the parliament.

Turkey has struck a one-million-ton oil supply deal with Libya after reducing imports of Iranian crude under pressure from the United States and international community, the Turkish energy minister said Tuesday.

Turkey's sole oil refiner Tupras agreed the deal with Libya and has started negotiations with Saudi Arabia for a long-term contract, Energy Minister Taner Yildiz was quoted as saying by the Anatolia news agency.

An earthquake of 6.0 magnitude hit off southwestern Turkey on Sunday, said the Istanbul-based Kandilli Observatory, as the local health director reported six to seven injuries but no deaths.

The quake, revised down from an initially reported magnitude of 6.1, struck at 1244 GMT off the small holiday resort of Oludeniz near Mugla province, said the institute.

Foreign Minister Adnan Mansour expressed optimism on Saturday that the upcoming days would hold positive news concerning the 11 Lebanese Shiite pilgrims abducted last month in Syria.

“The video aired by al-Jazeera television relieved us,” Mansour told Voice of Lebanon Radio (93.3).

Leaders of the exiled Syrian National Council met in Turkey on Saturday to pick a new leader after the resignation of Burhan Ghalioun last month to avert divisions in the opposition bloc.

The vote came as Western powers moved to slap sanctions on Damascus amid mounting anger over a massacre in a central village blamed on regime troops and fears of a full-fledged civil war in Syria.