Beirut: Six civilians suffered breathing difficulties and other symptoms indicative of poison gas inhalation after an attack launched by Turkey on the Kurdish- controlled enclave of Afrin, local doctors and Syria's state-run news agency report.

Jiwan Mohammed, a doctor at Afrin's main hospital, said on Saturday the facility was treating six people who had been poisoned who arrived on Friday night from the village of Arandi after it was attacked by Turkish troops.

Another doctor, Nouri Qenber, said the victims suffered shortness of breath, vomiting and skin rashes. One of the victims had dilated pupils, he said, quoting one of the rescuers. Both spoke to The Associated Press via messaging service.

State-run news agency SANA and the Britain-based Syrian Observatory for Human Rights monitoring group also quoted local doctors in their reports.

The claims could not be independently verified, and videos released from the hospital showed people being fitted with oxygen masks who did not otherwise show symptoms of poison gas inhalation such as twitching, foaming at the mouth or vomiting.

A White House official said the US was aware of the reports but cannot confirm them, and thinks it is "extremely unlikely" Turkey used chemical weapons against the Kurds. The official called for the protection of civilians.

SANA on Saturday said Turkey fired several shells containing "toxic substances" on a village in Afrin on Friday night, causing six civilians to suffer suffocation symptoms.

The Turkish military repeated in a weekly statement published on Saturday that it does not use internationally "banned ammunition" in its Afrin operation and said, "the Turkish Armed Forces does not keep such ammunition in its inventory."

The army also said it is careful to not harm civilians and only targets "terrorists" and their positions in the Afrin region.

AP