Assad's campaign to regain Idlib province, the last rebel bastion in a nearly nine-year-long civil war, has sparked a new exodus of thousands of civilians towards the border with Turkey, which backs some insurgent groups fighting Assad.
People were fleeing towns in southern Idlib, a Reuters witness said. Some headed towards camps for internally displaced persons or rebel-held towns near the Turkish border.
"When the air strikes began we fled our village and the area. We can no longer stay," said 39-year-old Mohammed Haj from the Jabal al-Zawiya region south of Turkey. "We don't know where to go, we just got in our car and left."
Heavy clashes broke out between rebels and government forces in Maarat al-Numan after the forces entered the town south of Idlib city, the Syrian Observatory for Human Rights said, after earlier reporting that the troops backed by Russian air strikes had taken full control.
Syrian state news agency SANA earlier said the army had "liberated most of the town's districts."
Maarat al-Numan, the second largest town in Idlib province, is located on the main highway linking the capital Damascus with Aleppo in northern Syria.
The renewed fighting comes despite a Jan. 12 ceasefire deal between Turkey and Russia, which back opposing sides of the conflict. Turkey's Defence Ministry said Turkish forces would retaliate "in the strongest way, without hesitation" against any attack on its observation posts in Idlib by Assad's forces.
Turkey already hosts more than 3.5 million Syrian refugees and fears millions more could soon cross the frontier."Today and yesterday there was a big exodus. There is heavy shelling in the areas south of Idlib," said Salman Eid, a 28-year-old from Talat al-Karama. "People took their children and belongings and are going to the camps."