Hundreds of Syrian soldiers in combat gear broke into houses and made arrests overnight in the Damascus suburb of Saqba, scene of a mass demonstration against the president last week, a resident said on Thursday.

"The soldiers did not say who they were. People think they are from Maher's Fourth division," the female resident, who did not want to be identified, told Reuters, referring to the president's brother Maher al-Assad.

"They cut off communications before they came in. There is no resistance. The demonstrations in Saqba have been peaceful. Scores of people have been arrested," she said.

Thousands joined a demonstration in Saqba last Friday demanding the removal of President Bashar al-Assad.

On Wednesday, army units backed by tanks tightened the siege of two defiant urban centres, a sign that Assad is widening the use of the military to crush demonstrations against his autocratic rule.

Tanks and armoured vehicles deployed around Rastan town and army units set up checkpoints in Sunni districts in Banias, days after the army division led by Maher al-Assad crushed protests in the southern city of Deraa with shellfire and machineguns.

Before the army stormed Deraa, the cradle of the Syrian uprising, Assad had relied mainly on security forces and secret police to confront the mass demonstrations.

"Assad's decision to use the army is pretty much the utmost escalation of force he can muster and a clear signal that he has no interest in any reconciliation," an Arab government official monitoring the situation in Syria said.

Assad belongs to the minority Alawite sect. His father Hafez ruled majority Sunni Syria for 30 years, succeeded on his death 11 years ago by Bashar.

The elder Assad extended Alawite control of the army, which is now led by mostly Alawite officers and effectively controlled by Maher al-Assad, military experts say.

The army and pervasive security apparatus underpin the power structure in Syria, fulcrum of several Middle Eastern conflicts. The ruling hierarchy has an anti-Israel alliance with Iran, but has kept the Golan Heights frontier with the Jewish state quiet since a 1974 U.S.-brokered ceasefire.

Rights groups say the army, security forces and gunmen loyal to Assad have killed at least 560 demonstrating civilians since the protests erupted in Deraa on March 18.

Last Friday military intelligence staff shot dead at least 17 demonstrators in Rastan, residents and rights campaigners said, after 50 members of the ruling Baath Party in the town resigned.

Tanks were deployed there after residents rejected a demand by Baath Party official Sobhi Harb that they hand over several hundred men in exchange for tanks staying outside the town.

MASS ARRESTS CONTINUE

In the mixed coastal city Banias, soldiers deployed on Wednesday in the main market area which separates Alawite from Sunni districts.

The army set up checkpoints in Sunni areas and arrested 10 people. Military intelligence turned back a convoy of vehicles loaded with food for the besieged quarters, a human rights campaigner in contact with Banias said.

Armed troops deployed in the Damascus suburb of Erbin and in the town of Tel north of the capital, where security forces arrested at least 80 men, women and children, the human rights organisation Sawasiah said.

"Five men over 70 years old were arrested. No one is escaping beatings and insults. Two mothers were taken as hostages because security forces could not find their sons," Sawasiah said in a statement on the Tel arrests.

The authorities say the unrest is caused by armed groups and infiltrators who have fired on civilians and security forces.

Wissam Tarif, executive director of the Insan human rights group, said family members had confirmed the detention of 2,843 people across Syria and the real number could be as high as 8,000. More than 800 of them had been taken from Deraa.

The United States, which had improved ties with Assad in the last two years, described the attack on Deraa as 'barbaric'.