Turkey and its rebel allies have opened up a new line of attack in northern Syria as Turkish tanks crossed the frontier from Kilis province, making a western thrust in an operation to sweep militants from its border.
The incursion from Kilis - an area repeatedly targeted by so-called Islamic State rocket fire over the last year - coincided with a push elsewhere in the region by the Turkish-backed Syrian rebels, who seized several villages further to the east.
By supporting the rebels, mainly Arabs and Turks fighting under the loose banner of the Free Syrian Army, Turkey is hoping to push out IS militants and check the advance of US-backed Syrian Kurdish fighters.
The rebels last week took the frontier town of Jarablus with Turkish support. The operation, called Euphrates Shield, is Ankara's first full-scale Syrian incursion since the start of the five-year-old war.
Today, the tanks crossed the border and entered the Syrian town of al-Rai to support the new offensive, a rebel spokesman and monitors said. Now under rebel control, al-Rai had previously been in the hands of IS.
Al-Rai is about 55 km (34 miles) west of Jarablus, and part of a 90-km corridor near the Turkish border that Ankara says it is clearing of jihadists and protecting from Kurdish militia expansion.
A rebel commander said they would aim to push east from al-Rai, in the direction of Jarablus, which would put pressure on IS from both east and west on a stretch of territory it controls along the border between the towns.
"The operations are to work from al-Rai towards the villages that were liberated to the west of Jarablus," Colonel Ahmed Osman of the Sultan Murad rebel group said, adding that the offensive was backed by Turkey.
While Euphrates Shield initially targeted IS in Jarablus, most of the focus since has been on checking the advance of US-backed Syrian Kurdish fighters, to the alarm of NATO ally Washington.
Turkey disagrees with its ally's support for the Syrian Kurdish YPG militia, which it considers a terrorist group. The YPG has been among the most effective partners on the ground in the US-led fight against IS.
Turkey is worried that advances by Syrian Kurdish fighters will embolden Kurdish militants in its southeast, where it has been fighting an insurgency for three decades led by the outlawed Kurdistan Workers Party (PKK).
