Syrian troops captured a village and a strategic hill from hardline militant groups on Monday in the northwest region of Idlib, regime media reported, as United Nations head Antonio Guterres called for action to prevent civilian casualties and mass displacement.
The Syrian government's advance was the deepest push so far this year into Syria's last major rebel stronghold. The latest wave of violence, which began April 30, has raised fears the government may launch a wider offensive to retake the area, home to around 3 million people. It is also the most serious challenge to a Russia-Turkey sponsored cease-fire in place since September. So far, 21 hardline fighters from the former Al-Qaeda affiliate Hayat Tahrir Al Sham and its ally in the Turkistan Islamic Party as well as 22 pro-government fighters have been killed in the violence. Thousands of civilians have been displaced and medical centres destroyed by regime and Russian airstrikes.
A senior Russian official said Russia's air base in the coastal province of Latakia came under fire from the insurgents, the latest assault on the military post since Friday.
Gen Viktor Kupchishin said the base was targeted twice on Monday by "multiple missile launcher systems." He blamed the attack on Hayat Tahrir Al Sham, the group in control of most of the rebel-held enclave. He said 36 missiles were fired using a drone but were repelled by the defence system. There were no casualties or damage, he said.
Insurgents in Idlib and Hama provinces, where the rebel-held enclave is located, have previously used drones to target the base. Most of those attacks were stopped, but they often serve to ratchet up tensions in the area.
Gen Kupchishin said the situation has "deteriorated dramatically" in the area. His comments were carried by Russia's state-owned Tass news agency.
Mr Guterres expressed great concern at the intensifying hostilities in what was supposed to be a de-escalation area and alarm at reports of aerial attacks on population centres and civilian infrastructure "resulting in hundreds of civilian dead and injured and over 150,000 newly displaced persons," UN spokesman Stephane Dujarric said.
Three health facilities were reportedly hit by airstrikes on Sunday, bringing the total to at least seven struck since April 28, Mr Dujarric said. Nine schools have reportedly been hit since April 30, leading to closures in many areas.
Mr Guterres called for an urgent de-escalating as the Ramadan begins, and he urged all parties to recommit to cease-fire arrangements agreed to last September, Mr Dujarric said.
Earlier Monday, the government-controlled Syrian Central Military Media said the village of Al Bani and the nearby Othman hill in the northern countryside of Hama province had been captured by Syrian troops.
The Britain-based Syrian Observatory for Human Rights, an opposition-linked war monitor, confirmed that Al Bani had been captured and that troops were marching toward the hill. The Observatory said the intense fighting on Monday killed 20 people.
Jaish al-Ezzat, one of the main rebel groups in the rebel-held enclave Syria, said it destroyed a Syrian army tank and that all the soldiers inside were killed. The group described "fierce clashes" near Al Bani.
The latest round of fighting has killed dozens and displaced tens of thousands in Idlib and nearby rebel-held areas, who fled to safer regions further north. It's the worst violence since September when Russia and Turkey negotiated the cease-fire to avert a government offensive on Idlib and surrounding areas.
The Observatory reported more than 60 Russian airstrikes on insurgents Monday alone.
Syria's state news agency SANA reported that Syrian troops intensified their shelling of insurgents in northern parts of Hama province and the southern parts of Idlib.