Anti-regime activists have posted videos online claiming to show rebels firing on army convoys in Syria's northern Idlib province as they head to Maaret al-Numan, a key city in rebel hands but under siege from government forces.

On Monday rebels from the "Maaret al-Numan's martyrs brigade" claimed they hit an army truck in a convoy headed to Maaret al-Numan.

And rebels from the "Dawn of Islam Brigade" using a machine gun mounted on a jeep claimed they also hit an army convoy headed there.

Journalists' movement is restricted in Syria and the government keeps a tight-lid on news related to a revolt which it blames on a foreign conspiracy.

However, these amateur videos have been found consistent with The Associated Press' own reporting from the region.

On Tuesday, Syrian warplanes attacked Maaret al-Numan and the village of Mar Shamsheh, as troops and rebels battled over a nearby Syrian military camp that has been under siege for days, according to the Britain-based Syrian Observatory for Human Rights, an activist group.

Rebels seized Maaret al-Numan earlier this month, hampering the regime's ability to send supplies and reinforcements to northwestern Syria, including Aleppo, where government troops are bogged down in a bloody fight for control of the city.

More than 34,000 people have been killed in the past 19 months, said Rami Abdul-Rahman, the head of the Observatory, which relies on a network of activists on the ground.

This figure includes civilians and rebel fighters, but also more than 8,000 regime soldiers, he said.