Israeli warplanes attacked a target on the Lebanese-Syrian border overnight Tuesday, foreign media reported on Wednesday. While some reports said the purported strike was carried out on the Syrian side of the border, according to one source the target was a weapons convoy that had crossed from Syria into Lebanon.

The reports come amid rising concern in Israel and the West regarding the sizable chemical weapons stockpile in the hands of an increasingly embattled Syrian regime.

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.

The Israeli military and the Prime Minister’s Office had no comment.

A Lebanese army statement said the last of the sorties was at 2 a.m. Wednesday. It said four warplanes, which flew in over the southernmost coastal town of Naqoura, flew for several hours over villages 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.

Reuters cited an unnamed Western diplomat and anonymous security source saying the planes had attacked a target near the Lebanese border with Syria.

“There was definitely a hit in the border area,” the source told the news agency.

The target of the attack was a weapons convoy, the French agency AFP reported, citing an unnamed security source.

Israel has been deeply concerned that chemical weapons from Syria could make its way into the hands of the south-Lebanon-based Hezbollah terror group due to the chaos of the Syrian civil war, and has said on several occasions that the transfer of chemical weapons to non-state actors, especially Hezbollah, would be a casus belli.

Another chief fear among Israeli security officials is that Hezbollah could get its hands on Syrian SA-17 anti-aircraft missiles. If that were to happen, it would change the balance of power in the region and greatly hinder Israel’s ability to conduct air sorties in Lebanon.

Israel believes that Damascus obtained a battery of SA-17s from Russia after an alleged Israeli airstrike in 2007 that destroyed an unfinished Syrian nuclear reactor.

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

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

The Lebanese army report did not mention if the planes entered Syrian territory, although the area of Lebanon where the flights reportedly took place borders southern Syria. The report of the flights was not corroborated by an Israeli source.

Israeli violations of Lebanese airspace are not uncommon, but Beirut officials say they have increased in the past few days.

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 nonconventional. All of it could find its way to our borders and not just to our backyards,” he said.

Mitch Ginsburg contributed to this report.