Syria has the world's biggest stockpile of chemical weapons  and its missiles and rockets can reach any part of Israel, the deputy head of Israel's military said.
It is the latest declaration by an Israeli official in what appears to be an orchestrated bid by the government of Benjamin Netanyahu, the prime minister, to pressure western governments to take more action in Syria.
Maj Gen Yair Naveh warned on Sunday about the size of Syria's chemical weapons arsenal  and its ability, and possible willingness, to use them on Israel.
If Damascus decided to use its chemical weapons, Gen Naveh said, it would "treat us the same way they treat their own people". 
Syria has not declared its chemical weapons stocks so the exact size of the arsenal is unknown.
He has joined a recent chorus of warnings and condemnations by Israeli officials of the regime of president Bashar Al Assad over its tactics to halt a 15-month-old uprising that has killed at least 9,000 and as many as 14,000 according to activist estimates.
On Sunday, Mr Netanyahu called government attacks on Syrians a "massacre" carried out with the help of Israel's primary regional foes,Iran and Hizbollah.
On the same day, Shaul Mofaz, Israel's vice premier, described the crackdown as "genocide" and demanded more involvement from the West, led by the United States. The president, Shimon Peres, also cheered on Syria's rebels, telling Israel Radio: "I hope they will win."
After hesitating to publicly take sides in the uprising, the burst of Israeli criticism unequivocally signalled a decision to back opponents of Mr Al Assad, political observers said.
But while Israeli leaders have broken with a policy of caution on the uprising, analysts and Palestinian officials differed on the reasons why.
Some described it as a way to reduce Iranian influence in the region, others see it as a ploy to divert attention from Israel's policies towards the Palestinians.
But either way, Yossi Alpher, the former director of the Tel Aviv University's Jaffee Centre for Strategic Studies, said there should no longer be any doubts about Israel's position on the uprising.
"This is a clear change, and it represents a determination by the government that we're better off without Assad," he said.
He and other analysts described Israel's previous position on Syria as "sitting on the fence". Israel was uncertain over what kind of government would replace the regime in Damascus. Despite their ties with Tehran and Hizbollah, Mr Al Assad and his late father, Hafez, both also kept Syria's boundary with Israel quiet for decades.
Last year, Israeli leaders began to publicly question whether Mr Al Assad could weather the insurrection. Then, in December, the defence minister, Ehud Barak, called the toppling of Mr Al Assad "inevitable".
But Palestinian officials criticised the amplified Israeli criticism on Sunday as a tactic to deflect attention from Israel's treatment of the Palestinians and the moribund peace process.
"So now, suddenly, they are verbally attacking the regime in Syria, as if this uprising started yesterday and as if Israel has suddenly become a protector of human rights in the region and over Syria," said Nabil Shaath, an official in the Fatah faction in the West Bank.
He compared the Syria criticism to Israeli leaders' recent warnings about Iran's suspected nuclear weapons programme.
Daoud Kuttab, an independent Palestinian analyst who lives in Jerusalem and Amman, said the recent statements on Syria suggested Israel had been "reassured" by the US and, possibly, opposition elements inside Syria.
"It seems to me that they've been reassured that what replaces Assad will be less anti-Israeli than the current regime, which explains the change," he said.
Mr Alpher also said Israeli leaders felt concerned about being seen as supportive, even if indirectly, of Mr Al Assad.
But Israel's primary motivation is the growing possibility that Mr Al Assad will be driven from power. That, in turn, will weaken Iran in the region, he said.
Mark Heller, the principal research associate at the Tel Aviv-based Institute for National Security Studies, agreed. The desire to break up the Syria-Iran-Hizbollah axis had begun to outweigh Israeli concerns about what could replace the Syrian government, such as an Islamist government.
Although describing this as trying to compare "the devil you know to the devil you don't know", Mr Heller added that coming out against Mr Al Assad had become the "lesser of two evils" for Israel.
* With additional reporting by the Associated Press
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