Fearing that Syrian chemical weapons could fall into the hands of Islamist militants, Israel is taking diplomatic and military steps to prevent it, local media and a security source said on Monday.
With unrest showing no signs of the bloodshed letting up in Syria, Israel on Sunday moved two batteries of its vaunted Iron Dome missile defence system to the north in case of military action against Syria or Lebanon becomes necessary, a security source told AFP.
Speaking on condition of anonymity, he said Israel believed Lebanon's Shiite militia Hezbollah has large forces in Syria that are supporting President Bashar al-Assad against Sunni rebels, but which would quickly snap up his chemical weapons if he falls.
Should that happen, "a decision to attack in Syria or Lebanon will need to be implemented immediately," he said.
"There won't be time then to start deploying."
The Israeli military tried to play down its redeployment of Iron Dome, saying only one battery had been moved north.
"As part of the operational deployment programme, which includes changing locations throughout Israel from time to time, (an) Iron Dome battery is currently in the north," a statement said.
Israeli Prime Minister Benjamin Netanyahu has also "urgently dispatched" his National Security Adviser Yaakov Amidror to Moscow over the Syria crisis, Maariv newspaper reported.
Amidror was to meet Russian Foreign Minister Sergei Lavrov to ask that Moscow use its influence to prevent the weapons from falling into the wrong hands.
Netanyahu also held talks on the issue with US ambassador to Israel Dan Shapiro on Sunday, the paper said.
Speaking to a delegation of US congressmen on Monday, Netanyahu said he was coordinating closely with Washington on the issue.
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"We have had very close cooperation on all things, including the developing matters in Syria, very close cooperation between our two governments," he said according to a statement from his office.
"This is important for the stability of the region, for the security of Israel and it's much appreciated."
In an interview with Israel's army radio, Shapiro said there were several threats they were hoping to prevent.
"There are two dangerous possibilities," he said. "Either the regime will use chemical weapons against the Syrian people, or the chemical weapons will pass to Hezbollah or to other extremist organisations.
"We want to prevent both those possibilities taking place."
Witnesses in northern Israel reported intense Israeli air force surveillance over Syria, with Home Front Defence Minister Avi Dichter confirming the Jewish state was watching in its neighbour closely.
"Israel, and not only Israel, is keeping an eye, a very close eye and trying to understand in the most precise way possible what is happening to the (weapons) stockpiles," he told public radio.
"It's a problem that has to be dealt with from two aspects.
"One is how to reduce what is (stockpiled) and the other is how to deter anyone intent on getting his hands on it, to let them know their hand will be badly burned if they even think about it."
Cabinet colleague Benny Begin said Israel was already preparing for the day after Assad.
"It looks like Syria will fragment into smaller sections and there will be a measure of anarchy there for some time after the fall of Assad," he told army radio.
"We have to prepare for what lies in store, and there is a responsible government doing just that."
Israel held elections on Tuesday, and in an unusual development the day after, Netanyahu reportedly convened emergency talks with his outgoing kitchen cabinet and the security establishment on Syria and the risk of it losing control of its arsenal of non-conventional weapons.