A roadside bomb allegedly planted by "terrorists" went off in Syria's northern province of Idlib on Sunday, killing six workers and injuring 16 others, the state-run SANA news agency reported.

The bomb, which was planted on the side of the road between Ariha and Masduma towns in Idlib, detonated when a bus transporting workers at Idlib spinning factory was passing by, said SANA.

The northern Idlib province has emerged as a hotbed of armed confrontation between troops loyal to Syrian President Bashar al- Assad and alleged army defectors who were given refuge in Turkey.

The Syrian government said that the turmoil in Syria is plotted by terrorists and foreign-backed armed gangs, and that more than 2, 000 army and security personnel were killed during the months-long unrest, while the United Nations put the death toll in the country at more than 5,000.