A Turkish court has sentenced a nephew of Fetullah Gulen, a cleric accused by Ankara, of orchestrating a 2016 coup attempt, to seven-and-a-half years in prison on terrorism-related charges.

Anadolu state news agency said on Tuesday that Selman Gulen was sentenced for being a member of a "terrorist" organisation. The prosecutor had asked for seven-and-a-half years to 15 years.

Selman Gulen told the court in the capital, Ankara, that he had met his uncle only once in his life, as he denied the allegations. He charged that the court was sentencing him only because he was a relative of Gulen and demanded his acquittal.

Turkey blames Fethullah Gulen and his FETO movement for a coup attempt on July 15, 2016, by a faction in the military.

Gulen has denied any role in the failed coup, which left more than 250 people dead and 2,000 injured. Once an ally of Turkish President Recep Tayyip Erdogan, he lives in self-imposed exile in the United States.

Turkey also considers Gulen's movement to be a "terrorist" group and has arrested thousands of people with alleged connections to him.

Turkish Defence Minister Hulusi Akar told parliament on Monday that 15,154 members of the armed forces have been sacked since the failed coup for their links to FETO. According to Anadolu, 326 of them have since got their jobs back.

On Tuesday, 70 people were arrested for their alleged connections to the movement in operations across Turkey, Anadolu reported. They included soldiers on active duty, former police officers and a medical student.

Last month, Turkey's interior ministry said nearly 218,000 people have been detained for their alleged links to the abortive putsch.