Nine Russian air strikes have hit hospitals or field clinics operating in war-torn Syria, killing civilians and medical staff, a Syrian medical organisation said late Thursday.

The Syrian-American Medical Society, which operates several facilities in Syria, said a deadly strike earlier this week "adds to the previous estimated eight Russian air strikes on hospitals in Syria, as well as the 313 attacks on medical facilities since the start of the conflict."

It said several of its facilities had been hit in Russia's bombing campaign, including in the Mediterranean coastal province of Latakia and the central province of Hama on October 2 and in the northwestern province of Idlib on Tuesday.

The latest strike killed two medical personnel and at least 10 civilians, and wounded 28 civilians, it said.

Russia has strongly denied reports that its aircraft hit the hospital in the Idlib province town of Sarmin, describing them as "fake."

The society's president, Ahmad Tarakji, called for international action to stop hospitals and clinics being hit again.

"We call on the international community to use all means necessary to end attacks on civilians and to prevent the further targeting of healthcare facilities in Syria," he said.

Russia began its air campaign in Syria on September 30 in support of its ally President Bashar al-Assad.

The campaign has been criticised not only for causing civilian casualties but also for targeting non-jihadist rebel groups more than the Islamic State group or Al-Qaeda.