Syrian forces shot dead seven civilians in the city of Homs on Monday, and unidentified gunmen killed four state workers, activists said, in one of the bloodiest days reported there since pro-democracy protests erupted.
Syria has faced international condemnation for its crackdown on a five-month uprising against the rule of President Bashar al-Assad.
Syrian authorities say they have deployed troops in Homs and in other Syrian cities in response to appeals by inhabitants frightened by "armed terrorist gangs".
The Syrian Observatory for Human Rights said pro-Assad troops stormed at least three neighbourhoods in the city, 165 km (100 miles) north of Damascus.
Unknown gunmen opened fire on a bus carrying employees of the state-owned Syrian Petroleum Transport Company, the Britain-based Observatory, headed by dissident in exile Rami Abdelrahman, added in statement.
The Observatory said witnesses reported gunfire and explosions in the city's five main residential districts and market.
Most independent media have been expelled from Syria, making it difficult to confirm reports.
The army deployed in Homs and occupied the main square four months ago after large protests demanding Assad's removal.
ReutersLast Mod: 06 Eylül 2011, 12:05