Activists fear an all-out assault on Homs during Monday, as Syria's embattled regime have stepped up troop presence around the flashpoint city and activated a security alert in Damascus after recent surprise protests.
The reported increase in security forces comes as the top US military officer, General Martin Dempsey, warned any intervention in Syria would be "very difficult" and that it was "premature" to arm the country's opposition movement.
Activists and Syrian state media reported that at least 14 people were killed on Sunday adding to growing death toll, which now numbers more than 6,000 people since the Syrian government started their 11-month crackdown on dissent.
"Infantry troops arrived yesterday (Sunday) in Homs," Rami Abdel Rahman, head of the British-based Syrian Observatory for Human Rights, told AFP on the phone Monday.
A Homs-based activist voiced fears about an imminent attack on Baba Amr, the main rebel stronghold in the central city, speaking of "unprecedented military reinforcements coming from Damascus."
"News has been leaked to us from army officers about a bloody attack that will burn everything in Baba Amr," Hadi Abdullah of the General Commission of the Syrian Revolution said on Sunday.
"We were expecting the attack two nights ago but it could have been just delayed because of the snowstorm," he added. Abdullah said regime forces pounded the defiant city at a rate of four to five rockets a minute for the 15th straight day on Sunday.
The Homs districts Bab Sbaa, Bab Dreib and Al-Safsafa were also targeted with sporadic shelling.
"We do not know when the attack might happen," Abdel Rahman said.
Meanwhile, regime forces remain on alert in Damascus after two days of unexpected popular protests following a call for a "day of defiance" which was observed in restive neighbourhoods, according to activists.
"Following the surprising demonstrations (on Friday and Saturday) the regime is reconsidering its security measures," said Abdel Rahman about the Syrian capital.
Activists reported on Sunday a security clampdown on the capital's central district of Mazzeh, thwarting plans to stage large protests in the area, after Saturday's funerals that became a huge anti-regime rally.
The funerals were for four people, including two teenagers, killed on Friday when security forces fired on protesters in Mazzeh, which houses many government offices and embassies.
The family of one protester, who was shot dead during Saturday's funerals, was forced by police to bury him early on Sunday morning, in an apparent attempt to prevent his funeral being turned into a protest, activists reported.
Mohammed Shami, a spokesman for activists in Damascus province, said on Sunday most shops were shut in Mazzeh as well as in the Barzeh, Qaboon, Kfar Sousa and Jubar districts.
Student demonstrations had been expected in Mazzeh but security forces where stationed around the schools, he said.
Nevertheless student protests erupted after school in other areas of Damascus, including the districts of Al-Hajar Al-Aswad, Midan, Jubar and Barzeh, according to Shami.
In central Damascus shops opened as usual, witnesses said, while state television showed live interviews from Mazzeh with people who claimed life was normal there.
Demonstrations took place in several towns elsewhere, including Herak in Daraa, Tayyana in Deir Ezzor, and the city of Jisr al-Shughur in Idlib, and northeastern Qamishli, according to the Local Coordination Committees, which organise protests on the ground.