Israeli media on Friday warned that an alleged air strike on a convoy carrying arms from Syria to Lebanon's Hezbollah could set off a chain reaction, and reported troops on high alert in the country's north.

Maariv daily reported that the Israeli military moved a third battery of its vaunted Iron Dome missile defence system to the northern Galilee region on Thursday, joining two others deployed from the south on Monday, one to the Haifa area and the other near the border with Lebanon.

"The Iron Dome system has been deployed in the north," an army spokesman told AFP, without commenting on numbers or location.

The spokesman insisted that the siting of the batteries was "routine."

There was still no official Israeli comment on Syrian claims that Israeli warplanes bombed a military site near Damascus on Wednesday or on separate reports that its aircraft struck a weapons convoy along the Syria-Lebanon border.

Newspapers, however, seemed to have little doubt on what had happened or the likely consequences.

"Complete restraint over the long term to Israel's actions could be considered weakness by Hezbollah, so we should expect some form of response, even if not immediately and not necessarily a broad rocket and missile attack on Israel," defence commentator Amos Harel wrote in the left-leaning Haaretz daily.

"The Hezbollah convoy, which according to foreign reports was attacked from the air while travelling from Syria to the Bekaa Valley in Lebanon, laden with explosives, will not be the last," Nahum Barnea wrote in Yediot Aharonot.

"It would seem, from a pessimistic view, that we are on the way to a military confrontation on at least one of the two northern fronts," he added, referring to Israel's borders with Syria and Lebanon.

The top-selling paper's front page said that the army's northern command had declared a state of high alert, but the military spokesman's office refused to confirm or deny this when asked by AFP.

The Syrian army said an Israeli strike early on Wednesday targeted a "scientific research centre" near Damascus, with local residents telling AFP it was a non-conventional weapons research centre.

Israel had frequently warned that if Syria's stockpile of chemical weapons fell into the Hezbollah hands, this would be a casus belli.

But the Jewish state has also raised the alarm over long-range Scud missiles or other advanced weaponry, such as anti-aircraft systems and surface-to-surface missiles, being transferred to the Lebanese Shiite militia.

"Efforts to transfer advanced weaponry to Hezbollah will continue, and will even accelerate as President Bashar al-Assad's regime continues to erode," wrote Israel Hayom, a free sheet considered close to Prime Minister Benjamin Netanyahu.

"On the assumption that Israel will know of this and will take action in the future, domestic pressure will mount in Syria and in Lebanon to respond, and this is liable to set the northern border on fire at any moment," it added.

Damascus has threatened to retaliate over the reported Israeli raid, and Syria's close ally Iran warned the attack would have "grave consequences."

The United Nations estimates that more than 60,000 people have been killed in Syria since the revolt against Assad's regime began in March 2011.

In Jerusalem on Friday about 200 Palestinians in the city's Al Aqsa mosque compound waved flags of the mainstream rebel Free Syrian Army and banners reading "Bashar must go!"