Several Syrian towns observed calls for a general strike on Saturday, a day after protests in which at least nine people were killed by security forces, activists said, dpa reported.
Most streets in the central city of Homs appeared deserted due to a large-scale security crackdown, the opposition group Local Coordination Committees of Syria said.
It added that several stores were burnt down in Bab al-Sebaa, a neighbourhood of Homs. Heavy gunfire was reported.
Meanwhile, a Syrian military source denied reports that explosions occurred early Saturday in the Military Academy in Homs.
He told Syria News, a private website, that an armed group had fired rocket-propelled grenades at the outside wall of the academy.
The source, who asked not to be identified, said the attack had caused no casualties.
State television reported Saturday that the driver of a Syrian passenger train died when his locomotive overturned as a result of sabotage to the rails in Homs.
Some 485 passengers on the train, which was travelling from Aleppo in the north to Damascus, survived the incident.
The television report said "subversive groups" had damaged the rails, showing footage of the damaged tracks and the train.
"For sure, it is a subversive act," Director of the Railways Authority in Homs George Essa told Syria News.
"The saboteurs removed parts of the rail tracks," he said.
Homs has for weeks been a centre of anti-government protests, which activists say have made the city the target of a draconian security clampdown.
The official Syrian News Agency SANA reported that army troops had rounded up what it described as members of armed groups in the city for blocking roads and terrorizing residents.
More than 1,400 people have been killed by security forces since pro-democracy protests began in Syria in mid-March, local human rights advocates say.
The reports are difficult to verify, as Syrian authorities have barred most foreign media and international human rights groups from the country.