A senior Turkish official has denied the claims by a monitoring group and Syrian state media that Turkey's military used chemical weapons on civilians in its operation against the Kurdish YPG fighters in northwestern Syria.

"It is out of the question for Turkey to use an internationally prohibited war tool in Afrin," Yasin Aktay, a chief adviser to the Turkish President Recep Tayyip Erdogan, told Al Jazeera over the phone on Sunday.

The Syrian Observatory for Human Rights (SOHR), a UK-based monitoring group, said six people were wounded in Turkish shelling in Al-Sheikh Hadid in the Afrin region on Friday had difficulties breathing and had their pupils dilated.

Al-Sheikh Hadid is located 30km to the west of the city of Afrin.

"Medical sources confirmed the use of gases during the shelling, but the SOHR was not able, until now, to know the type of the used gases," a statement by the group said.

{articleGUID}

SANA, the official Syrian news agency, quoting local doctors, repeated the claim, and said that six people were hospitalised with symptoms of suffocation from Turkish projectiles carrying poisonous gas.

Hediye Yusuf, a Syrian Kurdish politician, posted photos of several allegedly wounded men on Twitter on Saturday, claiming they were exposed to a sarin gas attack by Turkish forces.

‏Aktay, who is also a senior MP, said that the parties who accuse Turkey should prove their claims.

"The Afrin operation, and the Syrian war in general, have become a war of propaganda. And Turkey's rivals are trying to make up for the war they are losing on the ground through this propaganda," he added.

Aktay also said that the Turkish army was taking the operation slower than its potential to avoid civilian casualties.

"Generally speaking, if Turkey was not being utmost careful about not killing civilians in Afrin, and followed the methods [Syrian President Bashar] al-Assad implemented on his own people, this operation would probably have been concluded by now," he said.

The Turkish military has once again denied allegations that civilians were being killed in the operation in a statement on Saturday.

It also said that "1,614 terrorists" and 32 soldiers have been killed in the operation since it started a month ago.

YPG targeted

Turkey, together with the Syrian opposition forces it supports, last month launched an air and ground operation into the Afrin region to sweep the US-backed Kurdish People's Protection Units (YPG) fighters from its border there.

{articleGUID}

Turkey considers the Kurdish Democratic Union Party (PYD), active in Syria, and its armed wing YPG, to be "terrorist groups" with ties to the banned Kurdistan Workers' Party (PKK).

The PKK has waged a decades-long armed fight against the Turkish state that killed tens of thousands of people.

The PYD/YPG has come to control large swaths of northern Syria, including Afrin, in the course of the Syrian war, particularly through fighting against the Islamic State of Iraq and the Levant (ISIL) group in an US-backed umbrella organisation named Syrian Democratic Forces (SDF).

The US support for SDF has infuriated Turkey and created the ongoing diplomatic crisis between the two NATO allies.

Follow Umut Uras on Twitter: @Um_Uras