BEIRUT: Al-Qaeda's Syrian affiliate and other Islamist fighters made gains Friday in a joint offensive on the last major government-held bastion in northwest Idlib province, activists said.
The assault, which began Thursday, has seen the Nusra Front and allied groups seize a total of four checkpoints around the city of Jisr al-Shughur, the Syrian Observatory for Human Rights said.
"There are very fierce clashes ongoing since the early morning, and intense aerial bombing. The regime has conducted 34 airstrikes in the area since Friday morning," said Observatory head Rami Abdel Rahman.
He told AFP that the Nusra Front had conducted a series of suicide attacks on the city's outskirts and had sent 15 fighters with suicide belts into the city itself.
The Islamist coalition seized control of two checkpoints Friday morning and were battling pro-government forces for three others around the city, Abdel Rahman added.
He said that the clashes had left 13 rebels and 10 regime troops dead so far.
On its official Twitter and Facebook accounts, the Nusra Front posted pictures of explosives and destroyed buildings, saying it would "purify Jisr al-Shughur" from the Syrian army.
The local branch of the Syrian Revolution General Commission activist group said rebels began attacking the city from the north, leaving government forces "floundering."
The Syrian government made Jisr al-Shughur its de facto provincial capital after the same rebel coalition calling itself "The Army of Conquest" overran Idlib city last month.
The government still controls a smaller town, Ariha, to the east, and a military base in Al-Mastumah, just south of Idlib city.
But seizing Jisr al-Shughur would cut the government's access to a major highway linking Idlib to Latakia -- President Bashar Assad's home province -- further west.
If opposition groups overran it, they would be able to launch additional offensives on Latakia, said Charles Lister, visiting fellow at the Brookings Doha Centre think tank.
"This would be very dangerous for the regime," he said.
Nusra Front and its allies already control much of Idlib province.