The escalation has raised fears that a truce that lasted almost eight months in Idlib will be declared over.
Syrian government forces and their Russian allies have intensified their air offensive on the country’s rebel-held northwest for a fifth consecutive day in a widening campaign, killing and wounding dozens and forcing thousands to flee their homes.
After an overnight lull, government and Russian warplanes escalated bombings on Saturday hitting rebel areas in Idlib and the neighbouring province of Hama, aid workers in the area said.
The Syrian military sent new reinforcements towards Idlib, including tanks, armoured personnel carriers and hundreds of troops on Saturday.
The official SANA news agency said the army had destroyed “jihadist” positions in southern Idlib and nearby Hama province in response to what it called repeated violations of a de-escalation agreement.
But the UN humanitarian coordinator said schools, health facilities and residential areas have been hit and the government forces are employing the worst barrel bombing in at least 15 months.
Barrel bombs are containers packed with explosives dropped from helicopters.
“Now, the bombing has returned and is much heavier and has spread very widely in Jabal al-Zawiya and rural northern Hama,” Ahmad al-Dbis, safety and security manager for the US-based Union of Medical Care and Relief Organisations (UOSSM), told Reuters News Agency.
“The planes are not stopping at all and the bombing is continuing in a very big way like yesterday and worse,” al-Dbis added.
The recent upsurge in violence is the most serious in Idlib since Russia and Turkey negotiated a ceasefire in September.
The shaky truce had averted a major government offensive on the last rebel stronghold in Syria.
The Syrian Civil Defence, a rescue service operating in rebel-held areas, said it had recorded more than 30 deaths in the last few days.
Dbis said the number of dead was at least 50 while the UK-based Syrian Observatory for Human Rights (SOHR), which monitors the war, said at least 67 people had been killed.
Medical facilities bombed
Mustafa al-Haj Yousef, the civil defence director for Idlib, said more than 130,000 people had fled towards more secure areas, adding: “Civil defence centres have been targeted directly.”
UOSSM says four medical facilities have been bombed.
Over the past weeks, government forces have bombarded rebel-held areas while al-Qaeda-linked fighters attacked army positions around Idlib killing more than two dozen troops and pro-government gunmen over the past week, according to the AP news agency.
Idlib is the last major area of Syria still in rebel hands after a string of government offensives backed by Russian air power since 2015 turned the tables in a protracted civil war.
President Bashar al-Assad has regained control over most of the country, with the northeast held by Kurdish groups backed by the United States.
Idlib is held by an array of rebel groups, including the powerful Hay’et Tahrir al-Sham (HTS), a coalition of armed groups including those formerly affiliated with al-Qaeda.
Turkey, which has supported the rebels and has troops to monitor the truce, has been negotiating with Moscow to halt the air attacks with little success.