ANKARA, Turkey — U.S. Secretary of State John Kerry is expected to visit Turkey later this month, Turkey’s foreign minister said Friday, amid strained relations with Washington over the possible extradition of a Muslim cleric accused of being behind an attempted military coup last month.

The Turkish government has expressed growing annoyance with what it regards as a lack of solidarity from international allies in the aftermath of the failed coup, as well as increased frustration over perceived foot-dragging by the United States over a Turkish demand that U.S.-based Muslim cleric Fethullah Gulen be returned to Turkey to face trial.

Turkey accuses Gulen, a former ally of President Recep Tayyip Erdogan who lives in self-imposed exile in Pennsylvania, of masterminding the July 15 coup attempt by renegade officers in Turkey’s military. It has designated his movement, which runs charities, schools and businesses across the world, as a terrorist organization and has launched a widespread crackdown on suspected members.

Gulen has denied involvement or prior knowledge of the violent coup attempt that left more than 270 people dead. Washington for its part, has asked for evidence of the cleric’s involvement, and has said the extradition process must be allowed to take its course.

Turkish Foreign Minister Mevlut Cavusoglu said Kerry was scheduled to arrive in Turkey Aug. 24, the state-run Anadolu Agency reported. He also spoke of the possibility of a separate visit by U.S. Vice President Joe Biden.

Turkey on Thursday issued a warrant for Gulen’s arrest for allegedly ordering the failed coup, a move seen as a prelude to a formal extradition request.

In New York, Taha Ozhan, chairman of the Turkish parliament’s Foreign Affairs Commission who is leading a delegation to brief U.S. officials on the failed coup, said “Gulen orchestrated the coup” and continued to pose a threat to Turkey.

Ozhan said “many documents have been sent” and “we are doing our homework in Turkey” where “prosecutors are forming a case.” He added that the FBI should be monitoring Gulen and he should be detained.

“He’s still a threat and we don’t want to have another tsunami caused by July 15,” Ozhan said.

Since the coup attempt, nearly 70,000 people suspected of links to Gulen have been suspended or dismissed from the civil service, judiciary, education, health care and the military. About 18,000 people have been detained or arrested, mostly from the military, on suspicion of being involved in the failed putsch.

European officials and human rights groups have expressed concern over the crackdown.