A senior Israeli minister on Sunday issued Tel Aviv's most explicit call yet for military intervention to topple President Bashar al-Assad and accused him of committing genocide to suppress the 15-month-old uprising against his rule.
Vice Prime Minister Shaul Mofaz urged world powers to oust Assad in the same way that last year's Western-backed campaign in Libya overthrew former strongman Muammar Gaddafi.
"A crime against humanity, genocide, is being conducted in Syria today. And the silence of the world powers is contrary to all human logic," Mofaz told Israel's Army Radio.
"Since in the not-distant past the powers chose military intervention in Libya, here the required conclusion would be immediate military intervention to bring down the Assad regime."
Israel had so far taken a cautious line on the uprising in its Arab neighbour. While the overthrow of Assad would weaken his close ally and Israel's main enemy Iran, it has been wary of what might happen if the Syrian leader were to be replaced by an Islamist government more hostile to the self-proclaimed Jewish state.
The military chief, Lieutenant-General Benny Gantz, said last week he saw a "lose-lose prospect" for Israel whichever way the Syria conflict played out.
A belief that the uprising may have reached a tipping point and can no longer be rolled back has also given more space to hawks who see in Assad's fall an opportunity to weaken Iran - whose nuclear programme is Israel's biggest security concern.
Assad, from the minority Alawite sect, considered an offshoot of Shia Islam, has close ties both with Shi'ite Iran and the Lebanese Shi'ite political and military group Hezbollah, which was originally set up to oppose Israel.
But during his rule, Israel maintained what it believed to be a manageable standoff with Syria which might spin out of control were an organisation like the Sunni Muslim Brotherhood - ruthlessly crushed by his father Bashar al-Assad - to take charge next door.
Comments by Prime Minister Benjamin Netanyahu on Sunday, however, suggested that concerns about Iran may be starting to predominate in Israel's calculations.
"This is a slaughter carried out not only by the Syrian government. It is being helped by Iran and Hezbollah," he said in broadcast remarks to his cabinet. "The world should understand what kind of environment we live in."
Iran denies helping Assad to crush dissent.
Netanyahu has steered clear of explicitly calling for military intervention in Syria, telling Bild newspaper last week: "That's a decision for the leading powers who are now talking about it. The less I say as prime minister of Israel, the better."
Mofaz, a former top general and political centrist who became junior partner in Netanyahu's conservative coalition government last month, said Israel had limited options on Syria.
"We cannot get involved, for understandable reasons. But I think that the West, led by the United States, has an interest in guarding the threshold [so] genocide does not take place."
Soldiers and militias loyal to Assad have killed at least 10,000 people, including many majority Sunnis, according to U.N. figures.
The Assad government puts its own losses at more than 2,600 dead. It has condemned the killing of civilians in Syria, and blamed the violence on Sunni Islamist terrorism.
Israel's comments on Syria come at a time of intense frustration with the west's failure to curb Iran's nuclear programme. World powers have so far used sanctions and negotiations to stop a programe they believe is geared towards producing nuclear bombs. Israel has hinted it could attack Iran preemptively should it deem diplomacy a dead end.
Iran dismisses accusations it is secretly developing nuclear arms and has vowed wide-ranging reprisals if attacked, raising the spectre of a Middle East war in which Syria and Hezbollah would support Tehran against Israel.
Ehud Yaari, Middle East correspondent for Israel's top-rated Channel Two television, described Syria as a test-case for international resolve in the Middle East.
"When you see the lassitude [by world powers] regarding goings-on in Syria, you cannot but draw discouraging conclusions about their readiness to act to stop Iran," he said.
Israeli officials other than Mofaz have preferred to frame prospective foreign intervention in Syria in terms of humanitarian aid.
Deputy Foreign Minister Danny Ayalon on Sunday offered Israeli relief to Syrian refugees - either in countries like Jordan and Turkey that recognise Israel, or in Israel itself.