Turkey scrambled its warplanes yesterday and warned that it will respond to any violation of its airspace as Syrian jets bombed a rebel-held town near the border for a third day.
Turkish soldiers were monitoring the fighting from newly dug foxholes in the town of Ceylanpinar as gunfire crackled across the border, NTV television showed yesterday.
Turkish authorities used loudspeakers to warn residents to stay away as a Syrian jet dropped four bombs on the town of Ras Al Ain.
The attack came shortly after shelling by artillery units.
The forces of Bashar Al Assad, the president, have been trying to clear rebel forces from Ras Al Ain in clashes that have killed or wounded dozens of people over the past week and reignited tensions with Turkey. Busloads of rebel forces crossed from Turkey into Ras Al Ain, Hurriyet reported yesterday.
Israel, meanwhile, vowed to defend its borders and said that the Syrian regime had effectively lost control of the area that borders the Golan Heights.
The violence near the Israeli-occupied Golan has jarred the Jewish state, which had warned Mr Al Assad to prevent violence spilling over, but yesterday its defence minister, Ehud Barak, said the Syrian ruler's hold was undergoing "painful disintegration".
"Almost all of the villages at the foot of this ridge, and on upwards, are already in rebel hands," Mr Barak said on a visit to the Golan.
The prime minister, Benjamin Netanyahu, who accompanied Mr Barak, said Israel was worried its troops and settlers might come under fire and that enemy forces might penetrate the plateau.
Also yesterday, the Assad regime criticised France for recognising the legitimacy of the new Syrian opposition bloc. Faisal Muqdad, Syria's deputy foreign minister, said: "This is an immoral position because it allows the killing of Syrians. They are supporting killers, terrorists and encouraging the destruction of Syria."
In fighting yesterday, rebel fighters killed at least 18 soldiers as they overran a military post near Syria's northeastern border with Turkey.