ISTANBUL (AP) — Turkey’s leader told Donald Trump that his country will keep on fighting Syrian Kurdish militants even though they are a key U.S. ally against the Islamic State group, Turkey’s foreign minister said Thursday, adding that a top U.S. envoy should be fired for backing the Kurds.

Turkey considers the People’s Protection Units, or YPG, a terror organization and an extension of the Kurdistan Workers’ Party (PKK), which has waged a three-decade-long insurgency against the country. In April, the U.S. had criticized Turkish airstrikes against Kurdish militants in Syria and Iraq.

“Our president told his counterpart, clearly and plainly, that we would continue combatting YPG,” Foreign Minister Mevlut Cavusoglu told private NTV television Thursday while discussing Tuesday’s meeting between Recep Tayyip Erdogan and Donald Trump. “They did not say anything negative about this issue and treated it with understanding.”

The minister said Trump’s new U.S. administration seems more understanding about Turkey’s security concerns. He warned that senior U.S. diplomat Brett McGurk, in the anti-IS coalition, should not “poison” the administration by backing Kurdish groups.

“This McGurk is definitely supporting the PKK and YPG. It would be beneficial for this person to change,” he said.

He accused McGurk, the presidential envoy for the global coalition against IS, of carrying on Obama-era policies.

Cavusoglu said Turkey received U.S. assurances that arms sent to the YPG would only be used against IS, without explaining how this would be monitored.

“The weapons provided will only be used in Raqqa and its south, they will absolutely not be used against Turkey, this will not be allowed,” the minister said. “Turkey and the U.S. will together run an active combat against the PKK.”