More than 150,000 killed in Syria

The Syrian Observatory for Human Rights says more than 150,000 people have been killed in Syria since fighting began there three years ago.

A Syrian man runs past rubble as smoke billows in the background following a reported air strike by Syrian government forces (Getty/AFP).

More than 150,000 people have been killed in Syria's three-year conflict, as fighting continues to rage across the country, including an attack in the north that killed at least 31 people.

The Britain-based Syrian Observatory for Human Rights said that it has documented 150,344 deaths in the conflict that started in March 2011.

The figure includes civilians, rebels, and members of the Syrian military.

It also includes militiamen, fighting alongside President Bashar Assad's forces and foreign fighters battling for Assad's ouster on the rebels' side.

The Observatory bases its tally on the information the group receives from a network of informants on the ground inside Syria.

In January, the UN said it had stopped updating its own tally of the Syrian dead because it could no longer verify the sources of information that led to its last count of at least 100,000 in July.

Of the 150,344 people who died in the conflict, about a third, 51,212, were civilians, including 7,985 children and 5,266 women, The Observatory said.

The number also includes 26,561 rebel fighters and 35,601 Syrian soldiers as well as 22,879 Assad-loyal fighters and 11,220 foreign fighters battling on the opposition side. The number also includes unidentified casualties totalling 2,871.

Tuesday's attack in the northern town of Maaret al-Artiq came in the form of a barrel bombing - bombardment with containers stuffed with explosives rolled out of military helicopters, the Observatory said.

Syria's uprising began with largely peaceful protests against Assad's rule. It has evolved into a civil war with sectarian overtones, pitting predominantly Sunni Muslim rebels against Assad's government that is dominated by Alawites, a sect in Shiite Islam.

On Tuesday, The Observatory said fighting between Assad's loyalist and the rebels was concentrated in several opposition-held suburbs of the capital, Damascus, and the northern province of Aleppo, where rebels have managed to hold on to large swaths of territory and whole districts of the city of Aleppo, Syria's largest urban centre and its commercial hub.

The rebels captured them from government forces in a 2012 offensive.