The hospital on the outskirts of Hass, in the south of Idlib province, was hit by air strikes, in an attack captured on film by an AFP cameraman.

The raids were blamed on Russia by Syria Relief and Development, a non-governmental organisation that runs the facility, and the Syrian Observatory for Human Rights war monitor.

It is the fourth medical centre to have been put out of operation within a few days in an intensifying bombardment of the northwestern province and other adjacent territories held by jihadists.

"The hospital... is out of order because of the raids," said Ubaida Dandush, who works for Syria Relief and Development.

The facility had been evacuated shortly before the bombardments, he said, thanks to alerts from a warning system set up to analyse the flight paths of warplanes.

Footage filmed by the AFP cameraman showed a white cloud rising over farmland where the hospital is located.

The Britain-based Observatory said the facility had been put "out of service" because of "bombing by Russian aircraft".

The Observatory says it determines whose planes carried out strikes according to type, location, flight patterns and munitions.

Another seven civilians were killed on Sunday in bombardment by the regime and its ally Russia in other parts of the province, according to the monitor.

The Idlib region is under the administrative control of Hayat Tahrir al-Sham (HTS), which is dominated by a faction previously known as the Al-Nusra Front, before it renounced ties to Al-Qaeda.

Late last month the United Nations condemned attacks in northwestern Syria that damaged a medical centre and put two hospitals out of service.

Russia and rebel-backer Turkey in September inked a buffer zone deal to prevent a massive regime offensive on the Idlib region, near the Turkish border.

But the region of some three million people has come under increasing bombardment since HTS took full control of it in January.

The civil war in Syria has killed more than 370,000 people and displaced millions since it began with the bloody repression of anti-government protests in 2011.