Syrian soldiers fired shots in the air in the southern city of Deraa to prevent people attending Friday prayers or protesting, a resident said.

"They will open fire (on you) if you leave your house," the resident told Reuters by telephone. Tanks and soldiers poured into Deraa on Monday to crush resistance in the heart of Syria's six-week-old uprising.

Another resident said busloads of people were heading to Deraa from nearby villages, trying to converge on the city and demonstrate.

Meanwhile witnesses said Syrian Republican Guard trucks equipped with machine guns and carrying soldiers in combat gear patrolled the circular road around Damascus ahead of prayers on Friday.

Two other witnesses said various security units and secret police manned checkpoints around Damascus, cutting off the city from the suburbs and rural regions, as telecommunications and electricity were cut off from urban centres and towns that had defied warnings not to be the scene of anti-government protests.

Republican Guards was deployed in the suburb of Douma earlier this week and Assad sent the Fourth Mechanised Division under the command of his feared brother Maher to hit the city of Deraa, the cradle of the democratic uprising against his 11 year autocratic rule.

A senior Western diplomat said that despite army deployments, protests could still erupt across Syria after Friday prayers, the only occasion Syrians are allowed to gather en masse.

"If the protests turn out to be large, and I suspect that they will be, it will be another setback for the regime, which sent the army to the cities for the sole purpose of subduing the people," the diplomat said.

"The regime is already disappointed with how the military campaign is going. Deraa is resisting."-Reuters