Three children were killed Friday when an explosive device planted by unidentified gunmen went off in Syria's northern province of Idlib, according to private al- Ekhbariah TV.

The TV, which is close to the government, said the blast took place in the Kafr Takharim town of Idlib.

An eyewitness in the area confirmed the blast, telling Xinhua that he heard the sound of loud explosion in the area.

The Sham FM radio put the death toll of the blast at four civilians, without giving further details.

A day earlier, an unidentified group fired a mortar shell near a hospital in Idlib, but no human or material loss was reported, according to Sham FM.

The shell fell near a national hospital in Idlib's Jisr al- Shughur area, the radio quoted a military source as saying without further details.

Idlib, a province near the Syria-Turkey borders, has emerged as a hotbed of armed insurgency against the government forces.

The government of Syrian President Bashar al-Assad has accused Turkey of channeling weapons into the northern region for armed groups to carry on assaults against the government forces. The opposition, however, has been accusing the government of harshly cracking down on the opposition in the area and caused people to flee into Turkey.

The government forces 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.

Syrian Interior Ministry said Monday that specialized authorities had carried out over the past days a "qualitative" operation in Damascus suburbs and had tracked down "armed terrorist groups."

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.