The Syrian army started withdrawing tanks from the city of Homs after four days of assaults on opponents as Arab League observers arrive in the country, witnesses said.

Military forces launched a major artillery attack on the city despite agreeing to an Arab League plan to stop the bloodshed.

London-based Syrian Observatory for Human Rights put the death toll of civilians at 44 people on Monday. Among them, 34 rebels died in Homs during the bombardment of the neighbourhood of Baba Amr. Fifteen other bodies were found in the area.

Syria's third largest city was besieged by pro-government forces which left the population without food, water or electricity for days. France urged Prersident Assad al-Bashar to allow Arab League observers immediate access to Homs.

"The authorities in Damascus must imperatively, in keeping with the Arab League plan, allow the access of observers to the city of Homs," a spokesman for the French Foreign Ministry said. "The repression and unprecedented violence committed by the regime of Damascus must cease."

Fifty Arab League observers, from Jordan, Egypt and other Arab countries, have arrived in Syria. The Arab League said they would travel to Homs and other cities to monitor pledges by Bashar to withdraw government tanks and troops from cities.

In Cairo, an Arab League officialsaid the mission was the Syrian regime's last chance to reverse course.

"Will they facilitate the mission's work or try and curb its movements? Let's wait and see," the official said.

But independent critics and experts have raised concerns about whether the observer will work free from Syrian government pressure.

Global campaigning organisation Avaaz released figures that show that Syria's uprising has claimed at least 6,237 victims and seen 69,000 people detained since March. Other figures show that one in every 300 Syrians have either been killed or detained.

The Arab League plan includes government removal of security forces and heavy weapons from the streets. It also requires talks with opposition leaders and grants access to human rights workers and journalists.

Opposition members say the regime's agreement to the Arab plan is a farce.