By Tulay Karadeniz
ANKARA (Reuters) - Turkey said a suspected Syrian air strike had killed three of its soldiers overnight, in what appeared to be the first Turkish casualties at the hands of the Damascus government's forces since Ankara launched an incursion into Syria three months ago.
The attack occurred at around 3:30 am during a Turkish-backed Syrian rebel operation in northern Syria, the Turkish military said in a statement on Thursday.
The military said 10 other soldiers were wounded in the air strike that it "assessed to have been carried out by Syrian regime forces", but it gave no details on the exact location.
There was no immediate comment from the Syrian military. But it said in October the presence of Turkish troops on Syrian soil was a "flagrant breach of Syria's sovereignty" and warned it would bring down Turkish warplanes entering its air space.
Security and hospital sources in Turkey earlier blamed Islamic State fighters for the overnight attack and said it was in the al-Bab region. The wounded soldiers were transferred to hospitals in the Turkish border provinces of Kilis and Gaziantep, they said.
NATO member Turkey sent tanks, special forces and jets into Syria on Aug. 24 in support of largely Turkmen and Arab rebels in an offensive dubbed "Euphrates Shield" meant to push Islamic State and Kurdish militia fighters from its border.
President Tayyip Erdogan said last week that the Turkish-backed rebels were close to taking the Syrian city of al-Bab, the last urban stronghold of Islamic State in the northern Aleppo countryside.
Forces allied to Syrian President Bashar al-Assad warned Turkey last month against making any advance toward their positions to the north and east of Aleppo, saying any such move would be met "decisively and with force".
The Turkish-backed rebels have clashed with Syrian government forces before, including in late October, when a suspected Syrian government helicopter bombed their positions near Dabiq, a former Islamic State stronghold.
But Wednesday night's clash was the first time the Turkish military has said its own soldiers were killed by Syrian forces since Euphrates Shield began.
The attack came on the first anniversary of Turkey shooting down a Russian warplane over Syria, which prompted a lengthy diplomatic rift between Moscow and Ankara which only ended in August. Moscow is a major military backer of Assad.
(Additional reporting by Ercan Gurses and Tom Perry in Beirut; Writing by Daren Butler and Humeyra Pamuk; Editing by Nick Tattersall and Gareth Jones)