At least 13 people including two medical staff were dead after missiles hit a hospital in a northern Syrian town controlled by Turkey-backed fighters.

It was not immediately clear who was behind the shelling, which came from areas where government troops and Kurdish-led fighters are deployed.

The governor of Turkey's Hatay's province, across the border from Afrin, also said the attack killed 13 civilians and injured 27, adding that it involved rocket and artillery shelling of the hospital.

The governor's office blamed the attack on Syrian Kurdish groups.

A war monitor, the Britain-based Syrian Observatory for Human Rights, put the death toll at 18. The discrepancy could not be immediately reconciled.

The Syrian American Medical Society (SAMS) an aid group that assists health centres in opposition areas, said al-Shifaa Hospital in the town of Afrin was targeted by two missiles.

The attack destroyed the polyclinic department, the emergency and the delivery rooms, the group said.

Turkey and allied Syrian fighters took control of Afrin in 2018 in a military operation that expelled local Kurdish fighters and displaced thousands of Kurdish residents.

Ankara considers the Kurdish fighters who were in control of Afrin terrorists. Since then, there has been a series of attacks on Turkish targets in the area.

The head of the Kurdish-led Syrian Democratic Forces (SDF), Mazloum Abadi, denied his forces were behind the attack.

In a tweet, he said the US-backed SDF condemned the attack and called it a violation of international law.