A convoy of 30 tanks and up to 70 trucks filled with soldiers were seen on the circular highway surrounding Damascus today.
"Each truck had 20 to 30 soldiers. The convoy was either heading north in the direction of Homs or south in the direction of Deraa," said the witness, a former member of the Syrian army who did not want to be further identified.
Residents said tanks and armoured personnel carriers had been deploying at the northern edge of the restive town of Rastan.
The deployment followed the failure of an overnight meeting between residents and a ruling Baath Party official during which the official demanded the handover of several hundred men in the town.
The meeting followed pro-democracy protests on Friday during which security forces killed at least 17 demonstrators, the residents, who included a lawyer in the town, said.
Hundreds of Syrians have been charged with "degrading the prestige of the state", a Syrian rights group said, in president Bashar al-Assad's drive to crush pro-democracy protests against his 11-year autocratic rule.
The charge, which carries a three-year prison sentence, was lodged yesterday against hundreds of people detained this week ahead of the Muslim day of prayer on Friday, when the largest demonstrations calling for Mr Assad's overthrow are typically seen.
"Mass arrests are continuing across Syria in another violation of human rights and international conventions," said Rami Abdelrahman of the Syrian Observatory for Human Rights.
The campaign intensified after a tank-backed army unit, led by the president's brother Maher, last week shelled and machine-gunned into submission the old quarter of Deraa, cradle of the six-week-old uprising.
Wissam Tarif, executive director of the Insan human rights group, said 2,843 detainees had been verified by family members and the actual number could be as high as 8,000. More than 800 of them had been taken from Deraa.
Those detained across the country include activists, community leaders, people seen taking videos or pictures on mobile phones and people suspected of uploading videos on the internet, he said. But security forces were also randomly detaining people in Deraa and Douma, Mr Tarif said.
The demonstrations began with demands for political freedom and an end to corruption, but after a heavy security crackdown, protesters now want Assad to leave. Assad belongs to the minority Alawite Shia sect whose family has ruled majority Sunni Muslim Syria for 41 years.
Security forces have killed at least 560 civilians in attacks on demonstrators since the protests erupted in Deraa on March 18th, human rights groups say.
US state department spokesman Mark Toner said last night the use of tanks, arbitrary arrests and power cuts in Deraa was "...quite barbaric and amounts to the collective punishment of innocent civilians".
Amnesty International said protesters told the rights group they had been beaten with sticks and cables and were subjected to harsh conditions, including a lack of food.
"The use of unwarranted lethal force, arbitrary detention and torture appear to be the desperate actions of a government that is intolerant of dissent and must be halted immediately," Amnesty official Philip Luther said.
Residents of Damascus suburbs, where many were arrested, said roadblocks and arrests had intensified this week in areas around the capital.
At least six people were arrested yesterday after security forces took control of the coastal city of Banias, another urban centre where demonstrators are challenging the president.