Syrian government air strikes killed 18 civilians, including a dozen people at a busy market, as fierce fighting raged for the militant-held northwest, a war monitor said on Wednesday.

Regime forces battled to repel a militant counteroffensive around the town of Kafr Nabuda that has left 70 combatants dead in 24 hours, the Syrian Observatory for Human Rights said.

The Hayat Tahrir Al Sham alliance, led by Syria’s former Al-Qaeda affiliate, controls a large part of Idlib province as well as adjacent slivers of Aleppo, Hama and Latakia provinces.

The militant-dominated region is nominally protected by a buffer zone deal, but the government and its ally Russia have escalated their bombardment in recent weeks, seizing several towns on its southern flank.

At least 12 people were killed and another 18 wounded when regime warplanes hit the jihadist-held Idlib province town of Maarat Al Numan around midnight on Tuesday, the Observatory said.

The market was crowded with people out and about after breaking the daytime fast observed by Muslims during the holy month of Ramadan.

The bombardment blew in the facades of surrounding buildings, and ripped through the flimsy frames and canvas of stalls in the market square.

The bodies of market-goers were torn apart.

“Residents are still scared,” stallholder Khaled Ahmad told reporters.

Three more civilians were killed on Wednesday by air strikes in the nearby town of Saraqib, the Observatory said.

Two others were killed in strikes on the town of Maaret Hermeh, it added.

Another civilian was killed in air raids on the town of Jisr Al Shughur, the monitor said.

The Britain-based Observatory relies on a network of sources inside Syria and says it determines whose planes carried out strikes according to type, location, flight patterns and munitions.

The United Nations said on Wednesday that Idlib’s civilian population once again faced the threat of an all-out offensive.

“A full military incursion threatens to trigger a humanitarian catastrophe for over 3 million civilians caught in the crossfire, as well as overwhelm our ability to respond,” said David Swanson, a spokesman for the UN humanitarian office.

Swanson said more than 200,000 people have been displaced by the upsurge of violence since April 28.

A total of 20 health facilities have been hit by the escalation -- 19 of which remain out of service, Swanson said.

Collectively they served at least 200,000 people, he added.

Separately, US envoy James Jeffrey said on Wednesda that a ceasefire is needed in Syria’s Idlib province where there has been a recent upsurge in violence, and the United States is working towards halting the clashes, which have put tremendous pressure on civilians there,

“What we really need in Idlib and throughout the country is a ceasefire,” Jeffrey, US special representative for Syria engagement and special envoy to the global coalition to defeat the militant group, said at a House of Representatives Foreign Affairs Committee hearing.

“These conflicts, back and forth exchanges....just put tremendous pressure on civilians, they raise the specter of nation-to-nation clash,” he said.

“So we’re very much engaged in trying to get this stopped and get it back to the ceasefire we had basically since September.”

The strikes came as heavy clashes raged in neighbouring Hama province after the militants launched a counterattack on Tuesday.

Fresh fighting on Wednesday took the death toll to 70 -- 36 regime forces and militia and 34 militants, the Observatory said.

It said the militants had recaptured most of Kafr Nabuda from government forces, who had taken control of the town on May 8.

State news agency SANA on Wednesday however said the army repelled a militant attack in the area, killing dozens of insurgents.

Russia and rebel ally Turkey inked the buffer zone deal in September to avert a government offensive on the region and protect its three million residents.

But President Bashar Al Assad’s government upped its bombardment of the region after HTS took control in January.

Russia too has stepped up its air strikes in recent weeks.

The Observatory says nearly 200 civilians have been killed in the flare-up since April 30.

Agencies