Children and medical staff were among at least 18 civilians killed in air strikes that hit a hospital, market and village as the Syrian regime continues attempts to dislodge rebels from Aleppo province.

Rescue workers said the only hospital for women and children in the town of Kafr Hamra was partially destroyed in a new bombing on Friday, killing two members of staff including a nurse.

The Syrian Civil Defence group said it pulled 10 injured people from beneath the rubble, which provided vital medical services for the surrounding area.

Children were given emergency treatment and oxygen masks after a suspected gas attack in Aleppo on Thursday (Mahmoud Rashwani)

Hours later, air strikes hit a market in Urum al-Kubra, to the west of Aleppo city, killing at least six people according to the UK-based Syrian Observatory for Human Rights.

Children were among at least 10 other people reportedly killed in the bombing of the village of Hayan, where footage taken by opposition activists showed residents scrambling to recover the bodies of men, women and children strewn alongside a partially destroyed road.

No party in the conflict admitted the strikes but suspicion turned to Bashar al-Assad’s forces and their Russian supporters.

All three of the areas hit lie on strategic roads through opposition-controlled territory, linking Aleppo with the Islamist stronghold of Idlib and running north towards the Turkish border.

The attacks came as the United Nations started its investigation into a reported chemical attack by the Syrian regime on opposition areas of Aleppo city on Thursday.

UN says Russia’s three-hour daily truce is ‘not enough’ for Aleppo

At least seven civilians, including two children and their mother, were killed and scores more injured and left with breathing difficulties as doctors described a poisonous gas and the strong smell of chlorine.

President Assad’s government has repeatedly denied the use of barrel bombs and chemical weapons despite numerous reports throughout the civil war.

Staffan de Mistura, the UN special envoy for Syria, said experts were investigating Thursday’s attack after receiving “a lot of evidence”.

“If it did take place, it is a war crime and as such it would require everyone to address it immediately,” he added.

Doctors said the bombardment of health facilities was becoming so frequent that civilians were becoming afraid of going to hospital.

In July alone, aid organisations reported 43 facilities in opposition areas partially or totally destroyed.

Dr Hussein, who works in a hospital supported by Doctors Without Borders (MSF) in rebel-controlled eastern Aleppo, said essential services like paediatrics had been cut because of the number of civilians wounded in the war.

In pictures: Aleppo bombing Show all 14 1 /14 In pictures: Aleppo bombing In pictures: Aleppo bombing Bombing in Aleppo Smoke rises after airstrikes on the rebel-held al-Sakhour neighborhood of Aleppo, Syria April 29, 2016. Reuters In pictures: Aleppo bombing Bombing in Aleppo A Syrian family runs for cover amid the rubble of destroyed buildings following a reported air strike on the rebel-held neighbourhood of Al-Qatarji in the northern Syrian city of Aleppo, on April 29, 2016. AFP/Getty Images In pictures: Aleppo bombing Bombing in Aleppo A man reacts as he stands on blood stains at a site hit by airstrikes in the rebel held area of Aleppo's al-Fardous district, Syria, April 29, 2016. Reuters In pictures: Aleppo bombing Bombing in Aleppo The damage of the airstrikes in the rebel-held area of Aleppo on April 28 Reuters In pictures: Aleppo bombing Bombing in Aleppo The damaged the Medecins Sans Frontieres (MSF)-backed al-Quds hospital after it was hit by airstrikes, in a rebel-held area of Syria's Aleppo Reuters In pictures: Aleppo bombing Bombing in Aleppo Syrians evacuate an injured man amid the rubble of destroyed buildings following an air strike on a rebel-held of Aleppo on April 29, 2016. AFP/Getty Images In pictures: Aleppo bombing Bombing in Aleppo People inspect the damage at a site hit by airstrikes, in the rebel-held area of Aleppo's Bustan al-Qasr AP In pictures: Aleppo bombing Bombing in Aleppo A man leads a woman in tears and child out of the scene after airstrikes hit Aleppo AP In pictures: Aleppo bombing Bombing in Aleppo Civil defence members search for survivors after an airstrike at a field hospital in the rebel held area of al-Sukari district of Aleppo Reuters In pictures: Aleppo bombing Bombing in Aleppo A Syrian boy is comforted as he cries next to the body of a relative who died in a reported air strike in the rebel-held neighbourhood of al-Soukour in the northern city of Aleppo Getty Images In pictures: Aleppo bombing Bombing in Aleppo A Syrian family walks amid the rubble of destroyed buildings following a reported air strike in the Bustan al-Qasr rebel-held district of the northern Syrian city of Aleppo Getty Images In pictures: Aleppo bombing Bombing in Aleppo Syrian civil defence volunteers and rescuers remove a baby from under the rubble of a destroyed building following a reported air strike on the rebel-held neighbourhood of al-Kalasa in the northern Syrian city of Aleppo Getty Images In pictures: Aleppo bombing Bombing in Aleppo Syrians help a wounded youth following an air strike on the Fardous rebel held neighbourhood of the northern Syrian city of Aleppo Getty Images In pictures: Aleppo bombing Bombing in Aleppo Syrian civil defence volunteers evacuate people from a damaged building following a reported airstrike in the rebel-held neighbourhood of Tareeq al-Bab in the northern city of Aleppo

“The hospital has been damaged three times by bombings,” he added, listing attacks in July and on 3 and 6 August.

“The hospital is running at the moment but is able to care only for the most urgent cases.

“People are scared to go to hospitals – they see them as potential targets. They only come to us now if it is an absolute emergency."

The UN has repeatedly called on all parties to comply with obligations under international law to protect civilians and vital infrastructure but, despite promises of a regime-backed ceasefire, the violence continues in Aleppo.

The city, divided between government and opposition control, remains the scene of fierce fighting after predominantly Islamist rebels fought through regime lines to break a two-month siege last week.

Jaish al-Fath, an alliance headed by former al-Qaeda affiliate Jabhat al-Nusra, is being targeted by the Syrian regime and its Russian allies as a designated terrorist organisation.