Turkish prosecutors Wednesday demanded over four years jail for Turkish NBA player Enes Kanter on charges of insulting President Recep Tayyip Erdogan, state media reported.

The 25-year-old basketball player faces up to four years and eight months in jail for tweets posted last year, state-run Anadolu news agency said.

The New York Knicks centre has voiced support for US-based Muslim cleric Fethullah Gulen in Twitter postings after a coup bid last year aimed at ousting Erdogan.

Kanter, who has previously compared Erdogan to Adolf Hitler, lives in the United States and will be tried in absentia.

The date of the trial is not yet known.

While Turkey accuses Gulen of ordering the July 2016 coup bid, Kanter says the Gulen movement is a social initiative advocating human rights.

Ankara claims the group is a "terror" organisation but Gulen, who lives in self-imposed exile in Pennsylvania, denies this and any involvement in the attempted putsch.

Kanter's father was also briefly arrested in June while an arrest warrant had been issued for Kanter for alleged "membership of a terror organisation" in May.

Since July, over 55,000 people have been arrested over alleged links to Gulen and the coup bid while more than 140,000 public sector employees have been suspended or sacked in a crackdown which has raised concern in the West.

Thousands of Turks have also been prosecuted in recent years for allegedly insulting Erdogan but most of the complaints have not seen people jailed.