Syrian troops reclaimed a cluster of towns they lost early in the eight-year-old war, pressing an offensive in north-west, the country’s last major rebel stronghold.
The army drove out the last rebel fighters from the Hama countryside – the latest in a string of blows across Syria – and advanced on a Turkish military post.
Government forces pounded the south of Idlib province and nearby Hama from the air and the ground, prompting a new civilian exodus. Hundreds of people were killed in the campaign since late April, the United Nations says.
Rebel officials did not respond to requests for comment.
President Bashar al-Assad turned to Idlib after shoring up his rule in most of Syria with Russian and Iranian help.
The prospect of further advances in parts of the country outside his control is obstructed: in north-west by Turkey’s interests near its border and in north-east by US forces alongside Kurdish fighters.
Ankara backs rebel forces that control territory north of Idlib under its sphere of influence and some with a presence in Idlib.
Turkish President Tayyip Erdogan told his Russian counterpart Vladimir Putin Syrian army attacks were causing a humanitarian crisis and threatening national security.
In a phone call, Erdogan said the attacks violated a ceasefire in Idlib and damaged efforts for a solution in Syria, the Turkish presidency said.
The latest army gains put Turkish troops in Idlib in the firing line and threaten hopes of preventing a new wave of refugees on its border.
Many of the 500 000 people uprooted by the latest fighting in north-west fled toward the Turkey.
Under deals with Moscow and Tehran, Ankara has forces at a dozen military posts in Idlib region, including Morek, which the Syrian army entered on Friday.
Turkish Foreign Minister Mevlut Cavusoglu said the forces were not trapped.
“We are discussing this issue with Russia and Iran,” he told a news conference. “We are there not because we cannot get out, but because we do not want to get out.”
Russian-Turkish negotiations, including a truce deal to set up a “demilitarised” buffer zone, failed to end fighting in Idlib.
The Syrian army said itseized control of a handful of towns and environs in south Idlib and northern Hama, including Khan Sheikhoun, Kfar Zita and Morek.
“After heavy strikes in recent days and a full siege our brave soldiers managed to cleanse towns and villages,” its statement said. “The advance is continuing at a high pace.”
The latest push expands state control of a highway from Damascus to Aleppo, state TV said.
A live broadcast from Kfar Zita, under insurgent control since 2012, showed deserted streets and buildings pockmarked by shellfire.
Moscow and Damascus are responding to militant attacks by the former Nusra Front, a jihadist alliance now known as Hayat Tahrir al-Sham and is the dominant force in Idlib.