A car bomb hit the government-held city of Hama in central Syria on Sunday, causing multiple casualties, state television reported.
"A terrorist car bomb explosion went off near an agricultural vehicle company on the edge of Hama city," the broadcaster reported.
"Several people were killed or wounded."
The Syrian Observatory for Human Rights also reported the blast.
"A violent explosion shook the Sinaa highway in Hama city moments ago, followed by intense gunfire," the Britain-based group said.
"According to initial reports, the blast targeted a checkpoint manned by regime troops near an agricultural vehicle company, and ambulances could be seen in the area."
In the first months after the uprising against President Bashar al-Assad's regime erupted in March 2011, Hama saw some of the largest demonstrations against his rule.
But in late summer of that year, security forces stormed the city, killing scores of people. They have held a tight grip on the city ever since.
While several other Syrian cities have been engulfed by fighting, Hama has seen only sporadic violence in recent months.