Explosion in Syria kills 23 as military advances in strategic region

An explosion in Syria's northwestern city of Idlib killed at least 23 people and injured tens more, including civilians, a war monitor reported on Sunday.

The Britain-based Syrian Observatory for Human Rights said the explosion targeted the headquarters of a minor rebel faction in Idlib,a city located in a similarly named provinceinnorthwestern Syria.

The nature of the attack was not immediately clear. The monitor said there were conflicting accounts, attributing the explosion that shook the Thalatheen district of the city to either a car bomb or a drone attack.

Ambulances were deployed to the explosion site and rescue teams were continuing efforts to recover bodies and the injured from the rubble of the targeted building and neighbouring houses, the monitor added.

7 civilians among the dead

The majority of the deaths were fighters from the rebel group, in addition to seven civilians, with several people still unaccounted for, it said.

The bombing came hours after the Syrian military announced it had recaptured a strategically important town in eastern Idlib. The state-affiliated Al-Ikhbariya TV says government forces took Sinjar on Sunday.

The Observatory said the advance "opens the road" for the government troops to march on the rebel-held Abu Zuhour air base, about 19 kilometresto the north.

Idlib province is a stronghold of rebels in Syria and is situated on the border with Turkey, one of the main backers of rebellion against President Bashar al-Assad.

The Syrian army and its allies launched an offensive in October, with help from Russian airstrikes,to recapture the provinces of Idlib and Hama, and it has since been making swift advances. The main rebel force in Idlib is Tahrir al-Sham, spearheaded by the former al-Qaeda affiliate in Syria previously called Nusra Front.

The Syrian army lost Idlib to insurgents when the provincial capital fell in 2015. It became the only province fully under opposition control.

The offensive in Idlib gained more intensity on Christmas Day, when one of Assad's most trusted and experienced officers took command of the operation to extend the government's presence toward Idlib and boost security for the road that links the capital, Damascus, with Aleppo, Syria's largest city.

Brig.-Gen. Suheil al-Hassan, also known among his troops as Tiger,has led elite forces to many victories against insurgents since the conflict began nearly seven years ago.

The Idlib offensive carries significant risks.

Large-scale displacement is expected

The province bordering Turkey is home to more than 2.6 million Syrians, according to the UN, including more than 1.1 million who fled fighting elsewhere in the country. A full-blown government offensive could cause large-scale destruction and massive displacement.

Turkey, a supporter of the rebels, has deployed military observers in the province as part of a de-escalation deal with Iran and Russia, but that has not stopped the fighting on the ground or Russian airstrikes against the insurgents.

Four days after al-Hassan took over operational command, troops managed to break through the militants' heavy defences and capture the town of Abu Dali, a link between Hama, Idlib and Aleppo.

Since then, thousands of people have been fleeing with their belongings amid harsh cold weather toward safer areas further north, including Idlib city and areas near the border with Turkey.

Pro-opposition media say that more than 5,000 families have fled the violence over the past two weeks, some renting homes or staying in tents in open fields, others left homeless.

Syria has been embattled by a civil war since early 2011, when Assad cracked down on pro-democracy protests. Since then, hundreds of thousands of people have been killed and more than 10 million have been forced from their homes, according to the United Nations.