BEIRUT - Israel launched a rare airstrike inside Syria, U.S. officials said Wednesday, targeting a convoy believed to contain anti-aircraft weapons bound for Hezbollah militants in Lebanon. The attack adds a potentially flammable new element to tensions already heightened by Syria's civil war.
It was the latest salvo in Israel's long-running effort to disrupt the Shiite militia's quest to build an arsenal capable of defending against Israel's air force and spreading destruction inside the Jewish state.
Regional security officials said the strike, which occurred overnight Tuesday, targeted a site near the Lebanese border, while a Syrian army statement said it destroyed a military research center northwest of the capital, Damascus. They appeared to be referring to the same incident.
U.S. officials said the target was a truck convoy that Israel believed was carrying sophisticated anti-aircraft weapons bound for Hezbollah in Lebanon. They spoke on condition of anonymity because they were not authorized to speak about the operation. CBS News' David Martin at the Pentagon also reported Israel hit a convoy believed to be carrying weapons to Hezbollah.
Regional security officials said Israel had been planning in the days leading up to the airstrike to hit a shipment of weapons bound for Hezbollah, Lebanon's most powerful military force and a sworn enemy of the Jewish state. Among Israeli officials' chief fears is that Assad will pass chemical weapons or sophisticated anti-aircraft missiles to Hezbollah - something that could change the balance of power in the region and greatly hinder Israel's ability to conduct air sorties in Lebanon.
The regional officials said the shipment Israel was planning to strike included Russian-made SA-17 anti-aircraft missiles, which would be strategically "game-changing" in the hands of Hezbollah by enabling the group to carry out fiercer attacks on Israel and shoot down Israeli jets, helicopters and surveillance drones.
Hezbollah has committed to Israel's destruction and has gone to war against the Jewish state in the past.
A U.S. official confirmed the strike, saying it hit a convoy of trucks. All officials spoke on condition of anonymity because they were not authorized to discuss the strike.
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The Israeli military declined to comment.
Syria has long been among the militant group's most significant backers and is suspected of supplying with funding and arms, as well as a land corridor to Iran.
This strike, however, comes as Assad is enmeshed in a civil war with rebels trying to oust him. The rebels have seized a large swath of territory in the country's north and established footholds in a number of suburbs of the Syrian capital, Damascus, though Assad's forces still control the city and much of the rest of the country.
While Assad's fall does not appear imminent, analysts worry he could grow desperate as his power wanes and seek to cause trouble elsewhere in the region through proxy groups like Hezbollah.
The Syrian army statement denied that the strike had targeted a convoy headed from Syria to Lebanon, instead portraying the strike as linked to the civil war pitting Assad's forces against rebels seeking to push him from power.
"This proves that Israel is the instigator, beneficiary and sometimes executor of the terrorist acts targeting Syria and its people," the statement said.
The location could not be independently confirmed because of reporting restrictions in Syria.
Syria's government portrays the crisis, which started with political protest in 2011 and has since become a civil war, as a foreign-backed conspiracy meant to destroy the country.
Top Israeli officials have recently expressed worries that if desperate, Assad's regime could pass chemical weapons to Hezbollah or other militant groups.