BEIRUT — Syrian government troops pounded rebel-held villages around the northern city of Idlib with rockets, artillery and airstrikes, killing at least 29 people, including six children, activists said Monday.

After seizing the momentum in recent months in Syria's civil war, President Bashar Assad's forces are on the offensive against the rebels on several fronts, including in Idlib province along the border with Turkey. Government forces are in firm control of the provincial capital of same name, while dozens of rebel brigades control the countryside.

The Britain-based Observatory for Human Rights said government shelling overnight targeted five villages near Idlib city. Eight women and six children were among the 29 people killed, according to the Observatory.

The group, which relies on a network of activists inside Syria, said the deadliest attack took place in the village of Maghra, where a rocket slammed into a row of houses, killing 13 people. Three nearby villages — Bara, Basamis and Kafr Nabl — were hit by artillery shells that killed another 13 people. Three others died in an airstrike on the village Iblin, the Observatory said.

In central Syria, a car bomb exploded outside a police headquarters in the town of Deir Atiyeh, some 80 kilometers (50 miles) north of Damascus, killing 13 people, including 10 policemen. One child was among the dead, the Observatory said.

Syria's state news agency confirmed the attack late Sunday, but said a suicide bomber detonated an explosives-laden car in a residential area of the town, causing an unknown number of casualties. It said "terrorists" were behind the blast — a government term for rebels fighting to topple President Bashar Assad's regime.

There was no immediate claim of responsibility, but radical Islamic groups, including those with links to al-Qaida, frequently target Syrian government institutions, security installations and troops with car bombs and suicide attacks.

Last month, a Syrian branch of al-Qaida known as Jabhat al-Nusra claimed responsibility for multiple suicide attacks on security compounds in Damascus that killed at least five people.

The Nusra Front and other Islamic extremist groups have been the most effective fighting force on the opposition side in the past year, spearheading many of the rebel offensives that have captured military bases, towns and villages.

The U.N. estimates that more than 93,000 people have been killed in Syria since the revolt began in March 2011 with largely peaceful protests against the Assad regime. It turned into a civil war after opposition supporters took up arms to fight a brutal government crackdown.