Turkish war planes bombed Syrian Kurdish militia YPG and PYD targets in Kurdish-controlled Afrin, a senior Turkish official told Reuters on Saturday.
Two hours ago, at 14.00 GMT today, the Turkish military launched "Operation Olive Branch", with the stated aim to "…establish security and stability on our borders and region, to eliminate terrorists of PKK/KCK/PYD-YPG and Daesh, and to save our [Syrian] friends and brothers… from their [ the terrorists'] oppression and cruelty."
Direct military action against territory held by Kurdish militia opens a new front in Syria's civil war and sees Ankara confronting Kurds allied to the United States at a time when Turkey's relations with Washington are reaching breaking point.
Turkey's army said earlier it had hit shelters and hideouts used by militants from three groups – the Kurdistan Workers' Party (PKK), PYD and YPG, after militants fired on Turkish positions inside Turkey.
The Free Syrian Army has also started to support the Turkish military in Afrin, the official said.
Turkish President Tayyip Erdogan said earlier on Saturday that a military operation in the Afrin region had begun after cross-border shelling by the Turkish army.
The US-backed Syrian Democratic Forces accused Turkey on Saturday of using cross-border shelling as a false pretext to launch an offensive in Syria.
The SDF, an alliance of Kurdish and Arab militias fighting Daesh, said it would have no choice but to defend itself if attacked. The Kurdish-led SDF controls swathes of north and east Syria.