US officials told the New York Times on Wednesday that Israel notified the United States about an airstrike it carried out overnight Tuesday near the Lebanese-Syrian border.

The officials said that they believed the target of the strike was a convoy carrying sophisticated anti-aircraft weaponry intended to reach Hezbollah forces in Lebanon. 

An unnamed Western official told the Wall Street Journal that the convoy was carrying sophisticated SA-17 anti-aircraft weapons.

Israel has so far declined to comment on the strike. The Syrian Army issued a statement Wednesday accusing Israel of bombing a “scientific research center” in the Jamraya area just northwest of Damascus.

Two workers at the facility were killed and five were injured in the strike, the Syrian Army said, adding that considerable material damage was caused to the site, which was responsible for “raising the level of resistance and self-defense” of Syria’s military.

The statement denied that the strike was aimed at a convoy, and did not specify as to the purpose of the installation that was hit.

According to the report in the Wall Street Journal, US officials believe there may have been two strikes, one aimed at the convoy and another at a military facility.

Unconfirmed Lebanese media reports said the facility attacked contained chemical weapons.

The Syrian army portrayed the strike near Jamraya as linked to the civil war pitting Assad’s forces against rebels seeking to push him from power.

It said that “armed terrorist gangs”, a term the government uses to describe rebel groups, had tried and failed repeatedly to capture the same facility in recent months.

“This proves that Israel is the instigator, beneficiary and sometimes executor of the terrorist acts targeting Syria and its people,” the statement said.

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. Among Israeli officials’ 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, most recently in 2006 when Israel carried out a 34-day military operation targeting the group’s bases and infrastructure.

Lebanese officials said a dozen Israeli warplanes violated Lebanese airspace on Tuesday and overnight into Wednesday, flying close to the ground in several sorties over southern Lebanon.

A Lebanese army statement said the last of the sorties took place at 2 a.m. Wednesday. It said four warplanes flew in over the southernmost coastal town of Naqoura and hovered over villages for several hours in south Lebanon before leaving Lebanese airspace.

The Lebanese army said similar flights by eight other warplanes were conducted Tuesday, but added that it had no knowledge of an airstrike.

Earlier this week, Israel moved a battery of its new “Iron Dome” rocket defense system to the northern city of Haifa, which was battered by Hezbollah rocket fire in the 2006 Israel-Hezbollah war. The Israeli army called that move “routine.”

Israel Military Intelligence Chief Aviv Kochavi is in Washington for consultations at the Pentagon, including meetings with Joint Chiefs of Staff head Martin Dempsey.

Vice Prime Minister Silvan Shalom said Sunday that any transfer of arms to Hezbollah “would be crossing a line that would demand a different approach.”

On Tuesday, Air Force chief Amir Eshel said Israel needed to be wary of both conventional and non-conventional weapons finding their way out of Syria.

“There is, in Syria, an enormous arsenal of weapons, some state of the art and some non-conventional. All of it could find its way to our borders and not just to our backyards,” he said.

Tuesday’s strike was Israel’s first inside Syria since September 2007, when warplanes destroyed a site that the UN nuclear watchdog deemed likely to be a nuclear reactor. Syria denied the claim, saying the building was a non-nuclear military site.

Syria allowed international inspectors to visit the bombed site in 2008, but it has refused to allow nuclear inspectors new access. This has heightened suspicions that Syria has something to hide, along with its decision to level the destroyed structure and build on its site.

In 2006, Israeli warplanes flew over Assad’s palace in a show of force after Syrian-backed militants captured an Israeli soldier in the Gaza Strip.

And in 2003, Israeli warplanes attacked a suspected militant training camp just north of the Syrian capital, in response to an Islamic Jihad suicide bombing in the city of Haifa that killed 21 Israelis.

Syria vowed to retaliate for both attacks but never did.

Despite tensions, no special alerts were recorded in the north of Israel. Municipal bomb shelters, normally opened when the security situation warrants it, remained closed Thursday morning, Israel Radio reported.

AP and Mitch Ginsburg contributed to this report.