At least 13 people were killed when a car bomb exploded on a busy roundabout in the central Syrian city of Homs on Sunday, the Syrian Observatory for Human Rights monitoring group said.
Another 40 people were wounded in the explosion in the mainly Alawite Zahraa neighborhood, it said. Some of the dead were security forces loyal to President Bashar Assad, an Alawite, who is fighting a three-year revolt against his rule.
Car bombs have become frequent in Homs in the past weeks, in particular since Assad's forces moved into previously rebel-held areas of the city this month.
The uprising against Assad began as peaceful protests but became militarized after heavy crackdown by his forces, taking on an increasingly sectarian nature, pitting majority Sunni Muslims against Alawites, followers of an offshoot of Shi'ite Islam.
Syria became a magnet for foreign al Qaeda-linked fighters who now control some rebel-held areas of the country.