The offensive has already forced thousands of civilians to abandon their homes and flee for their lives.
Overnight, government forces and its Russian ally launched hundreds of air and ground strikes on the southern and eastern countryside of Idlib, according to the Syrian Observatory of Human Rights, apparently paving the way for the ground push.
Residents and activists reported incessant bombing over the last few days. In a widely circulated video, a resident of Maaret al-Numan, a town southeast of the rebel-held enclave that has been heavily targeted in the last few days, pleaded for help to evacuate the area. He asked for vehicles.
"It has been a hard and difficult night for the people of Maaret al-Numan," the unidentified man said. "Whoever can come and get us out please."
Hundreds of displaced marched to the border crossing with Turkey, demanding access to safety and calling for an end to the violence. The militants who dominate Idlib opened fire over their heads to disperse them.
Syrian state media posted pictures of troops in Um Jalal, one of the four villages they captured and which lies southeast of Maaret al-Numan.
The Observatory said at least 11 civilians were killed in Maaret al-Numan and its suburbs and farther north since Thursday.
Before this latest bout of violence, the U.N. reported that some 60,000 Idlib residents had been displaced in recent weeks by the government offensive.
Syrian government forces have been slowly chipping away at the rebel-held Idlib, despite a fragile Russian-brokered cease-fire in September 2019. The overstretched Syrian army has been waging a limited offensive against the province.
Since the cease-fire, the government has been pushing to clear access to a strategic highway that links the capital Damascus and northwestern city of Aleppo.
Idlib is home to 3 million civilians and the U.N. has warned of the growing risk of a humanitarian catastrophe alongside the Turkish border.
Mahmoud Najib al-Youssef, from a village southeast of Maarat Numan, said he and his family fled after three days of intense bombing that saw bombs explode even near a school. The bombing emptied his village, Deir Sharqi, he said. Then the bombs followed them, and they had to move one more time to an area near the border with Turkey.
Al-Youssef said people take advantage of periods of calm, often shortly after dawn, to flee.
"Life has come to a standstill" in the village, he said. "Doctors left, pharmacies closed and groceries too."