Syrian regime forces have taken control of several towns in northwestern Idlib province, a war monitor and Syrian state media reported, amid a renewed push by Bashar Assad to recapture the last opposition stronghold.
Hundreds of thousands of people have fled Idlib in recent weeks amid stepped up air strikes by Russian and regime forces aimed at clearing the opposition from its last redoubt after almost nine years of war.
The Syrian Observatory, a war monitor, said on Sunday that six towns in the Idlib countryside had fallen to regime forces in the past 24 hours.
The Observatory said the regime advance, backed by heavy Russian airstrikes, has brought Assad's forces to the outskirts of Maarat al-Numan, which lies about 33 km (20 miles) south of the city of Idlib.
The mainly deserted city of Maarat al-Numan is a strategic prize lying on the M5 linking Damascus to Syria's second city Aleppo, a main highway coveted by the regime as it seeks to regain control of the entire country.
Regime forces now reached "the edges of the city and are... within gunfire range of part of the highway", said the Observatory.
The push deeper into opposition-held territory has taken place despite a deal between Turkey and Russia, which back opposing sides in the conflict, for a Jan. 12 ceasefire.
Turkish President Recep Tayyip Erdogan said on Friday that around 400,000 people from Idlib province were moving towards the Turkish border as a result of the surge in violence.
Turkey, which has a presence in the area and is seen by many civilians as a protector against Russian strikes, already hosts more than 3.5 million Syrian refugees and fears that millions more could cross the border.
Moscow and Damascus say they are fighting extremists that have stepped up attacks on civilians in Aleppo city in northern Syria, but rescue workers and rights groups say air strikes have hit civilian areas including hospitals and schools.
Since December 1, some 358,000 Syrians have been displaced from their homes, the vast majority of them women and children, according to the United Nations.
Aid agencies and relief groups have warned that further violence could fuel what may potentially become the largest wave of displacement seen during the conflict.
