JERUSALEM -- Israelis rushed to get government-issue gas masks yesterday, the latest sign of mounting fears that the Syrian regime could lose control of its chemical weapons stockpiles and violence could spill over the border.
Until a few days ago, the possibility of being dragged into Syria's civil war was not a major issue in Israel, whose leaders have had a laserlike focus on the potential threat posed by Iran's suspect nuclear program. That changed when President Bashar Assad's grip on Syria turned more doubtful last week, following startling military gains by rebels and a bomb attack that killed four top officials.
Syria then threatened to unleash chemical and biological weapons if the country faces a foreign attack; Syria is believed to have nerve agents as well as mustard gas.
Israeli officials are more worried about the possibility that the weapons could fall into the hands of Islamic militants from Lebanon's Hezbollah or other groups, should the regime fall.
"For us, that's a casus belli, or red line," Israeli Foreign Minister Avigdor Lieberman said. He told Israel Radio that the government would act immediately to prevent that from happening as tensions rise along Israel's northern border.
The fighting also has hit too close for comfort with the thud of exploding mortar shells on Syrian territory near the Israeli-controlled Golan Heights, captured from Syria in 1967.
That has drawn Israelis with binoculars to a strategic plateau, seeking a glimpse of the battle and expressing concern for their nearby homes.
Syria and Israel fought two wars, in 1967 and 1973, and have failed to reach a peace deal because of disagreements over the fate of the Golan Heights. Assad and his late father, Hafez, had kept the frontier with Israel quiet, however.
Some Israeli officials fear that a power vacuum in Damascus could turn the Golan into a haven for militant groups, much as Egypt's lawless Sinai Peninsula has attracted a variety of anti-Israel radicals since the fall of Hosni Mubarak.
Israeli Defense Minister Ehud Barak disclosed over the weekend that he had asked the military to prepare for a possible attack on targets in Syria to secure strategic weapons if the regime collapses. Prime Minister Benjamin Netanyahu followed suit with a similar threat.