43 Syrian civilians killed by Assad barrel-bomb raid

At least 43 civilians were killed and 150 wounded in a Syrian government air raid targeting the Islamic State (IS) group in the northeast, a monitoring group said on Wednesday, updating an earlier toll.

"The strikes hit a cattle market in the Tal Hamis area, which is controlled by IS," said the Britain-based Syrian Observatory for Human Rights, which relies on a wide network of activists and doctors for its reports.

Previously it had said 27 people were killed in the Tuesday raid.

Tal Hamis lies in Hasakeh province which is mainly controlled by Kurdish militia or forces backing president Bashar al-Assad, but where IS militants hold some areas.

The Syrian Revolution General Commission, which represents a unified coalition of opposition groups that aim to establish a democratic government, said at least 65 people were killed in the attack.

"The barrel bomb attack turned the market into a lake of blood. The bodies of the victims could not be identified due to the severe bomb explosion. The victims included women and children," the commission said in a statement.  

The pro-government newspaper Al-Watan said dozens of IS members were killed in the operation south of Tal Hamis.

IS militants "have been using the cattle market as a base for trafficking illegally pumped oil," it said.

Assad's government is reportedly among those buying oil from IS.

IS controls a number of oil fields in eastern Syria and Washington says they provide the group with significant revenue.

The militants' black market oil infrastructure has been repeatedly targeted by US-led air strikes.

"There are daily regime and (US-led) coalition airstrikes against IS positions in Hasakeh," Observatory director Rami Abdel Rahman told AFP.

Tuesday's bombing was especially deadly because it struck a cattle market.

"Some of the bodies were so mutilated by the strikes that people couldn't tell the human from the animal remains," said Abdel Rahman.

Earlier Tuesday, the Observatory reported a string of airstrikes against the town of Saraqeb and the village of Sheikh Mustafa in the northwestern province of Idlib.

Eleven civilians were killed in Saraqeb, and another man died in Sheikh Mustafa, according to the group.

Most of Idlib's countryside is out of government control, but its capital remains in government hands.

Syria's civil war began in March 2011 as a peaceful protest movement inspired by the pro-democracy Arab Spring and demanding the overthrow of Assad, but morphed into a brutal war after pro-Assad forces unleashed a massive crackdown against dissent.

The war has resulted in the deaths of an estimated 200,000 people, and displaced roughly half of the country's population, according to the UN. 

The majority of fatalities are reportedly of civilians, primarily killed by pro-Assad forces, although other groups are also implicated.