The Syrian army sent tanks in to the city of Hama overnight Tuesday to Wednesday, according to residents there, and troops have raided a number of houses searching for activists.
Meanwhile, latest videos posted on the internet claimed to show fresh anti-government protests in Al-Haraa on Tuesday. Activists and locals say two people were shot dead there and two more elsewhere in the Deraa province.
Most foreign media have been barred from Syria, making it difficult to verify the claims.
More pictures were said to come from Damascus on Tuesday. In the background protesters could be heard chanting slogans against President Bashar Al-Assad. In the foreground, uniformed and plainclothes forces moved to contain the situation.
There was no easing of the military crackdown during the holy month of Ramadan, which ended in Syria on Tuesday.
The United Nations estimates some 2,000 civilians have been killed in five months of protests against 41 years of Assad-family rule.