JERUSALEM: Israel may have maintained total silence over Syrian claims it hit a military centre near Damascus, but the Jewish state has vowed to do whatever it takes to stop advanced weapons from reaching Hezbollah.

Over the past week, Israeli officials have stepped up the rhetoric about Syria's weapons stockpile, which includes chemical agents, warning of dire consequences if they end up in the hands of the Iran-allied Lebanese militia against which it fought a devastating war in 2006.

But following reports of a pre-dawn strike Wednesday on a weapons convoy heading for Lebanon, coupled with accusations by Syria of an Israeli hit on a military research centre near Damascus, official Israel fell silent.

"The best thing that Israel has been hoping for for a long time is that the West will take control of these weapons," admitted Tzahi HaNegbi, an MP who is close to Prime Minister Benjamin Netanyahu.

"Israel has always said that if sophisticated weapons coming from Iran, North Korea and Russia fell into the hands of Hezbollah, it would cross a red line," he told army radio.

"But the world is not ready to take such a decision as it did in Libya or Iraq, so Israel finds itself facing a dilemma which we alone can resolve," he said, saying Israel was left with no choice but to take preventative action.

If Israel had indeed attacked military targets in Syria, it was to prevent Hezbollah from changing the strategic balance of power in the region, former top army officer Dan Harel told the radio.

"We are not ready to accept that Hezbollah changes the balance of force," said Harel, former deputy head of the Israeli military.

"We have said it many times in the past. If Israel did do what is claimed, it was to maintain the military balance with Hezbollah," he said.

Israel has said Hezbollah obtaining chemical weapons would be a casus belli which would cause it to act "without hesitation or restraint" but the Jewish state has also warned about the militia obtaining other advanced weaponry, such as anti-aircraft systems and surface-to-surface missiles.

Commentators said it was unlikely that the convoy which was attacked was carrying chemical agents, suggesting it could have been transporting anti-aircraft missiles which could damage Israel's aerial abilities over Lebanon.

"Israel is particularly concerned about the Russian-made SA-17s because they could substantially restrict the Israel Air Force's freedom of movement over Lebanon, an area where today it can operate virtually unhindered," wrote Haaretz's defence correspondent Amos Harel.

Commentators said the modus operandi was very similar to the 2007 bombing of a Syrian nuclear facility, widely understood to be an Israeli strike but never acknowledged by the Jewish state, which remained silent over the raid.

"The reasoning was that as long as Israel didn't claim responsibility, it would be possible for Syrian President Bashar al-Assad to deny that anything ever happened, and therefore he wouldn't feel obliged to respond," wrote Harel.

"The critical question is what Hezbollah... will do."

So far, Hezbollah's only response has been a strongly worded condemnation issued early on Thursday in which it denounced "a new Zionist aggression against Syria."

But it made no mention of revenge, prompting speculation in Israel it was likely to hold its fire -- for now.

Earlier this week, Israel transferred two batteries of its vaunted Iron Dome anti-missile system to the north, and press reports also spoke of a spike in demand for gas masks.

"When engaging in such activities, we could face an attack by Hezbollah or possibly Syria, that's why we must prepare our defences and Iron Dome is part of that," former top military intelligence official Danny Rothschild told army radio.

Despite the heightened tension in the north, pundits said it was unlikely the strike would spark an immediate escalation.

"The signs have increased recently that the winds of war are blowing in the north," said the Maariv daily.

"That said, all the assessments are that the attack -- which did or didn't take place, would not lead to an immediate round of fighting in the north.

"Hezbollah's arsenal is reserved first and foremost for the day that Israel attacks Iran and not as a response to an attack on an arms convoy."