The current course of U.S.-Turkey relations “does not bode well,” Turkish President Recep Tayyip Erdogan said before departing the United Nations General Assembly in New York on Thursday.

In a wide-ranging briefing to Turkish journalists, Erdogan highlighted divisions between the NATO allies over Turkey’s purchase of a Russian missile defense system and its consequent removal from the U.S.-led F-35 stealth fighter aircraft program.

“I cannot honestly say that there is a healthy process in Turkish-American relations,” the president was reported as saying in the Turkish media. “Look, we bought the F-35s, paid $1.4 billion, and these F-35s were not delivered to us.”

He added: “It is my hope that, as two NATO countries, we should treat each other with friendship, not hostility. But the current trajectory does not bode well.”

Erdogan said he had worked well with all the U.S. presidents during his 19-year rule but “I can’t say that we started well with Mr. Biden.”

Looking ahead to his scheduled meeting with Russian President Vladimir Putin in the Black Sea resort of Sochi on Sept. 29, Erdogan said they would discuss bilateral relations and Syria, particularly the situation in Idlib, the final rebel stronghold in the country.

Erdogan also addressed his call for reform of the U.N. and said he had proposed the “radical step” of removing the veto power of the Security Council’s five permanent members through an extraordinary meeting of the General Assembly “when necessary.”

Questioned about the new Taliban government in Afghanistan, Erdogan said it was unfortunate that an inclusive leadership had not been formed earlier this month, when the group revealed an all-male cabinet of hardliners.

“There are signals coming that there may be some changes, that there may be a more inclusive atmosphere in the administration,” he said. “If such a step can be taken, then we can move to the point of discussing with them what we can do together.”

Turkish and Qatari technicians have been working to fully reopen Kabul airport following the withdrawal of foreign forces from Afghanistan last month.