Kurdish forces in Syria and the Syrian Observatory for Human Rights have reported a suspected gas attack in the country carried out by Turkish forces Friday. The Turkish government has denied the claims.

Doctors in Syria spoke to several local and international news outlets, claiming they had to treat six civilians after a Turkish shelling in Syria's Afrin region. The six people allegedly suffered shortness of breath, vomiting and skin rashes — indicators of a chemical attack.

Turkey, which has launched a January offensive in Northern Syria to root out Kurdish forces, maintained that it has not used chemical weapons and that the reports were propaganda.

“It’s just a fabricated story. Turkey has never used any kind of chemical weapons,” Turkish Foreign Minister Mevlut Cavusoglu told reporters Sunday at the Munich Security Conference.

The shelling took place in Northern Syria, near the Turkish border. Villagers were transported to a hospital in the city of Afrin, though video of the victims did not appear to show the same symptoms doctors spoke about, according to the Associated Press.

Turkey has fought Kurdish forces in Syria, called People's Protection Units (YPG), in a military initiative called Operation Olive Branch. Turkey considers YPG to be a terrorist organization. Cavusoglu has accused YPG of using civilians as human shields.

A White House official told the AP that it was “extremely unlikely” that Turkey used chemical weapons in Syria.

The U.S. has provided support to YPG as they fought to rid Syria of ISIS, but has indicated that it is against a Kurdish movement for autonomy. A seven-year-long civil war in Syria allowed ISIS to fester and control parts of the country. ISIS, however, has lost almost all of its territory.

Combat has continued in the region despite calls this month by the United Nations for a humanitarian cease-fire.