(Reuters) - Israel believes there is no immediate risk of Syria´s chemical weapons falling into the hands of militants, a senior minister said on Tuesday, despite its growing worries about fighting there which has prompted Israeli calls for outside military intervention.

"At this stage, the Syrian regime has firm control over the chemical weapons arsenal, but there are al Qaeda elements in Syria and therefore we are maintaining close scrutiny," Vice Prime Minister Moshe Yaalon, a former armed forces chief, said.

Israel, initially cautious about any change of government in Syria - a neighbor with which it has had a manageable standoff until now - has come out recently with increasingly strong calls for an end to the rule of President Bashar al-Assad.

This week it accused Assad of committing sectarian "genocide" and urged foreign military intervention to topple him.

Its main worry is that Assad could transfer Syria´s chemical weapons - which Western powers believe is the world´s largest stockpile - to its ally, the Iranian-backed Lebanese political and military organization Hezbollah, in any desperate bid to retain power by spreading Syria´s military arsenal.

The possibility of them falling into the hands of foreign fighters affiliated to al Qaeda is a secondary concern, though Amos Yadlin, former head of Israeli military intelligence, played down the prospect of them being able to use them.

"These are very complicated systems that terrorist groups would find it hard to contend with," he said. "They would be more likely to hurt themselves with such materials, than others."

The comments from Yaalon saying he believed Assad had firm control of the chemical weapons, therefore, had all the more resonance coming from a country which has strong reasons to ring alarm bells if it believes these are at risk.

His remarks, made in a speech, followed media speculation that Israel could mount a preemptive strike to prevent chemical arms falling to Syrian rebels or being transferred to Hezbollah.

The deputy commander of Israel´s armed forces, Major-General Yair Naveh, said Syria´s missiles could deliver chemical warheads anywhere in the Jewish state.

"We thought we had already distanced ourselves from the subject of existential war," Naveh said at a briefing, a video clip of which was circulated to the media. "To our regret, we are slowly returning anew to this reality."

Defence Minister Ehud Barak said separately Israel worried that "advanced or non-conventional weaponry" could reach Hezbollah "the moment the (Assad) regime falls."

Syria is one of just eight states - along with Israel and nearby Egypt - that have not joined the 1997 Chemical Weapons Convention, which means the world´s chemical weapons watchdog has no jurisdiction to intervene there. The Assad government has in the past denied having weapons of mass destruction.

Israel struck preemptively at the suspected nuclear weapons projects of Syria in 2007 and of Iraq in 1981, and has threatened to take similar action against Iran.

But Israel has not pursued such a strategy against enemy chemical programs. Many experts believe that Israel regarded its military supremacy - reputed to include the region´s only nuclear arsenal - as enough to ward off any chemical attack.

An Israeli military officer briefed on contingency planning said there had been no unusual preparations for any action on Syria. (Editing by Myra MacDonald) (© Thomson Reuters 2012. 06/12/12)