* Israel faces possible conflict on three fronts
* Fears "strategic looting" of Syria's advanced weaponry
By Dan Williams
HERZLIYA, Israel, May 22 (Reuters) - Israel is prepared to attack Syria to prevent advanced weapons reaching jihadi rebels or Hezbollah guerrillas in Lebanon if President Bashar al-Assad is toppled, Israel's air force chief said on Wednesday.
Major-General Amir Eshel also said Israelis should brace for a protracted and painful conflict should their forces engage in combat with Hezbollah or its main backer, Iran.
"If Syria collapses tomorrow, we will need to take action to prevent a strategic looting of advanced weaponry," he told the Fisher Institute for Air & Space Studies near Tel Aviv.
"We have to be ready for any scenario, at a few hours' notice," Eshel said.
He assumed fighting could escalate on to three fronts at once and require the Israeli air force to employ "the full spectrum of its might".
Israeli warplanes have attacked Syria at least three times this year to destroy what intelligence sources described as advanced anti-aircraft and ground-to-ground missile caches in transit to Hezbollah. The Israelis also worry that Assad may lose control of Syria's chemical warheads stocks.
Beset by the more than two-year-old insurgency, Assad has not retaliated for the air strikes. But some Israeli experts worry his forbearance could wear out - especially if he believes new Russian-supplied air defences will let him fend off his militarily superior foe.
Eshel said the most formidable of the Russian systems, the S-300, was "on its way" to Syria and that Israel could not afford to see its air superiority dented given what he predicted would be the need to hit the other side intensively.
"If we want to prevail within a few days, we need to use a lot of firepower, and quickly," he said. "Air superiority is critical, and we must contend with a new generation of capabilities."
Israelis would be mistaken to anticipate a repeat of their lopsided recent clashes with Palestinian guerrillas in Gaza, or their 2006 war with Hezbollah in south Lebanon, Eshel told Reuters on the sidelines of the conference.
"People are looking for a knock-out, for things to be surgical and sterile, but they won't be. The homefront will be hit, no matter how much we defend it," he said, referring to possible missile attacks on the Israeli interior from Syria, Hezbollah and Iran.
"If we go to war in the north, we can win, without a doubt, but it will be something entirely new. No one should say, 'Guys, we are fighting without pressure, so we will finish this story in two months.' It's far more delicate than that." (Writing by Dan Williams, Editing by Jeffrey Heller and Angus MacSwan)
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