Invitation of the PKK terrorist group Syrian offshoot the Democratic Union Party (PYD) to Russia-backed Congress of Syrian peoples is "unacceptable," Presidential Spokesperson Ibrahim Kalın said Wednesday.

Axar.az reports citing Daily Sabah that Kalın said that it was impossible for Turkey to accept the invitation of terrorist PYD and its armed wing People's Protection Forces (YPG).

"We do not see any problems in inviting Kurds, who are not from PYD/YPG, but PYD/YPG is a terrorist organization. We will not accept inclusion of a terrorist group into a platform like Astana [talks on Syria]," the presidential spokesperson said.

According to Kalın, the problem was "mostly" solved, but Turkey will not welcome such initiatives in the future.

When asked about controversial independence referendum held by the Kurdistan Regional Government (KRG), Kalın said that everyone, including Turkey, expected the KRG to completely cancel the results of the illegal Sept. 25 vote.