Supplies are dwindling in the main hospital of Syria's Afrin city, which has taken in 48 people killed and 86 wounded in recent Turkish attacks, its director said on Wednesday.

Ankara launched an air and ground offensive nearly two weeks ago against the Afrin region, opening a new front in Syria's multi-sided war to target Kurdish fighters in northern Syria.

"We call on the United Nations to stop the Turkish aggression," Khalil Sabri, head of the Afrin city hospital, said at a televised press conference. "The medical situation is getting worse in Afrin, and the medical supplies we have are about to run out," he said.

Since the onset of Syria's conflict in 2011, the Syrian Kurdish YPG militia and its allies have set up three autonomous cantons in the north, including Afrin which borders Turkey.

Syrian rebel factions, which are fighting alongside Turkey in its offensive, control territory around Afrin. The Syrian army also holds a patch of land bordering the canton.

The YPG spearheads an alliance of militias, the Syrian Democratic Forces (SDF), that has seized vast territory from Islamic State militants with help from the U.S.-led coalition.

The SDF said Turkish forces and their rebel allies shelled a neighbourhood in Afrin city on Wednesday, wounding 12 civilians.