Ankara: The Turkish-US relations could be affected if Washington does not extradite cleric Fethullah Gulen whom Ankara accuses of being behind the July 15 coup attempt, Foreign Minister Mevlut Cavusoglu said on Monday.

Turkey will accelerate efforts for the extradition of Gulen, Xinhua news agency quoted Cavusoglu as saying.

Turkey has repeatedly said the coup attempt was organised by the followers of Gulen.

However, the cleric who has been living in a self-imposed exile in the US for years, denied any involvement, calling the accusation "insulting".

"I am sure US President [Barack] Obama, the US intelligence and Secretary of State know this coup [attempt] was made by Gulen," Justice Minister Bekir Bozdag said.

Bozdag also warned that the relations between the two countries will turn sour if Gulen maintains his life in the US after the attempt.

"The US government does not have any justification in defending and keeping Gulen," Bozdag said.

More than 44,000 employees of state institutions were suspended amid a nationwide probe into the coup attempt for suspected links to Gulen.

The coup attempt was crushed the next day with at least 290 people, including more than 100 "coup plotters", killed, authorities said.