The unprecedented surge in air strikes carried out by Syrian forces this week is a desperate attempt by President Bashar al-Assad's regime to reverse recent gains by rebel fighters, analysts and rebels say.

The air raids, they say, are not so much aimed at hitting rebel positions but at striking enough fear and provoking enough anger to turn local populations against the opposition fighters in their midst.

"The militants have seen significant gains in the last few weeks, especially in the north, and the Syrian air force sees this as a major threat," said Charles Lister, a London-based analyst with IHS Jane's Terrorism and Insurgency Centre.

"The increase in the strikes is spurred by these relatively significant military gains," he said.

Monday saw the regime carry out its heaviest air strikes since air power was first deployed in mid-summer, with more than 60 raids across the country, according to the Syrian Observatory for Human Rights, a key watchdog.

Intensive air raids have continued, targeting rebel-held areas in the eastern suburbs of Damascus and the northwestern Idlib province, especially around the town of Maaret al-Numan seized by rebels in early October.

A fighter jet even hit targets for the first time inside the city limits of Damascus near a rebel-held suburb on Tuesday, as the rebels claimed responsibility for killing a top air force general.

The strikes came as regime forces repeatedly failed to push rebels out of their bastions around the capital and after opposition fighters gained new footholds in the northwest.

Maaret al-Numan, which sits on the main road linking Damascus with the embattled northern commercial hub of Aleppo, was a particularly important gain, analysts said.

"The regime's resort to such a heavy use of airstrikes is a sign that it is losing the battle," the head of the main rebel Free Syrian Army (FSA) forces in Aleppo, Colonel Abdel Jabbar al-Okaidi, told AFP by telephone.

"The army has no troop presence in the areas it is bombarding and it is resorting to all-out destruction from the skies," Okaidi said.

But far from being precision strikes on rebel positions, the air raids are haphazard attacks on civilian areas, often with the crudest kind of explosives, analysts said.

"These are dumb bombs, not smart bombs, and when you are using them you are not trying to gain any tactical advantage," said Riad Kahwaji, head of the Dubai-based Institute for Near East and Gulf Military Analysis.

In many cases aircraft are simply dropping so-called barrel bombs -- canisters stuffed with dynamite, oil and chunks of steel -- causing widespread destruction over civilian areas, he said.

Analysts said the strategy is to kill civilians, destroy their homes and make their lives so unbearable that they force the rebels out, or at least stop providing them with assistance.

"They are trying to make the civilian population so angry and so scared that it will not be possible for the rebels to find safe havens," Kahwaji said.

"The only objective is to terrorise the civilian population with the hope they will turn against the rebels."

Without civilian backing, the rebels will have little hope of holding territory, Lister said.

"If the civilians turn against the militants, that has a significant impact on their ability to hold on to areas and to defeat the military," he said.

So far the strategy seems to be having little effect, observers said.

"They have bombarded Maaret al-Numan every day for three weeks, ever since the rebels took control there. There may be casualties, but the army has been unable to re-enter the town," said Rami Abdel Rahman, director of the Britain-based Observatory.

In fact, the regime's strategy may be having the reverse of the desired effect, Kahwaji said, by fuelling public fury.

"Using strategic bombing in an insurgency, against rebels, has never been successful," he said. "You are only angering the population and making them ask for blood in return."