JERUSALEM - Syrian rebels control almost all the villages near the frontier with the Israel-held Golan Heights, the Israeli defense minister said Wednesday, bringing the conflict dangerously close to the Jewish state and raising the possibility of an armed clash with the region's strongest power.

During a tour of the Golan Heights, Defense Minister Ehud Barak gave a scathing assessment of Syrian President Bashar Assad's forces and said Israel will remain "vigilant and alert."

"Almost all of the villages, from the foot of this ridge to the very top, are already in the hands of the Syrian rebels," said Barak, who was accompanied by Prime Minister Benjamin Netanyahu. "The Syrian army is displaying ever-diminishing efficiency."

The civil war in Syria has renewed tensions over the Golan Heights, a strategic plateau that Israel captured from Syria in 1967. Despite hostility between the two countries, Syria has been careful to keep the border quiet since the 1973 Mideast war.

But in recent days, Israeli troops have fired into Syria twice after apparently stray mortar shells flew into Israel-held territory.

While it is widely believed that Assad does not want to pick a fight with Israel, there are fears the embattled Syrian leader might try to draw Israel into the fighting in a bout of desperation. Israeli officials believe it is only a matter of time before Syrian rebels topple the longtime leader.

Israeli political scientist Dore Gold, an informal adviser to Netanyahu, said it's difficult to assess whether Israel is better off with rebels in control along the border.

"The forces fighting the Assad government are made up of diverse elements. And to make a judgment whether Israel should be more or less worried, that would require having a very precise picture of what's going on there, which we don't," he said. "But it's no secret that among the Syrian rebels are forces that identify with al-Qaida, and are a cause of concern."

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