The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, said rebels withdrew from Idlib province's Maarat al Numan town late on Tuesday.
Syrian regime forces are in full control of a key rebel-held town in the country's northwest after days of intense fighting and air strikes that displaced tens of thousands of people, the Syrian regime army said Wednesday.
The capture of the town of Maarat al Numan, in Idlib province, marks another defeat for forces opposed to regime leader Bashar Assad.
Regime forces which now control most of Syria after a nearly nine-year conflict that left more than 400,000 people dead and displaced half of Syria's population.
Syrian regime forces have been on the offensive for more than a month in northwestern Idlib province, the last opposition and militant stronghold in the country. But in recent days, the regime captured more than a dozen villages in the area as the insurgents' defences began to crumble.
Al Qaeda-linked militants control some parts of Idlib province and small parts of the adjacent area in Aleppo.
Regime army spokesman Brig. Gen. Ali Mayhoub listed more than a dozen villages and towns captured, including Maaret al-Numan, during an operation carried out by Assad's forces.
The Britain-based Syrian Observatory for Human Rights, an opposition war monitor, said rebels withdrew from the town late on Tuesday.
Syrian regime troops had left a road west of the town opened apparently to give a chance for insurgents to pull out and to avoid street battles inside the town.
The push into Maarat al Numan came as regime forces were also advancing against rebels west of the city of Aleppo, according to state media and opposition activists.
Maarat al Numan, which had been in the hands of anti-Assad Arab forces since 2012, sits on the highway linking Damascus with Aleppo, once Syria's main commercial hub.
With the town's fall, regime forces are now closer to retaking the critical north-south highway.
The regime offensive in Idlib has led to the displacement of hundreds of thousands of people, many of them to areas close to the border with Turkey.
The province is home to 3 million civilians, and the UN has warned of the growing risk of a humanitarian catastrophe along the Turkish border.
In August, Syrian regime troops captured another town along the highway, Khan Shaykhoun.
Now that regime troops are in control of Maarat al Numan, their next target is likely to be Saraqeb, which would become the last major town on the M5 highway that remains outside regime control.