A group of armed "terrorists" attacked on Friday some border guards near Syria's central Homs province, killing three of them, including a colonel, the private Sham FM radio reported.

The attack occurred in Dar al-Kabir area on the borders with Lebanon, said the report without further details.

Also in Homs, unidentified gunmen stormed an infirmary in Bustan al-Diwan area and set it ablaze after robbing its contents, according to the report.

Meanwhile, in northern Idlib province, an explosive device went off in Siraj village in Jabal al-Zawya region, leaving two people injured, according to Sham FM radio.

Earlier in the day, four people were killed, including three children, when an explosive device planted by unidentified gunmen went off in the Kafr Takharim town of Idlib.

The government forces have escalated the crackdown over the past days on violence in restive areas in central and northern Syria as well as Damascus suburbs, as the leadership pledged to beat "terrorists" with an iron grip.

The Syrian government said more than 2,000 army and security personnel have been killed during the months-long unrest, while the United Nations put the death toll in the country at more than 5,400.