Turkish authorities say they have suspended 1,500 prison personnel and guards over links with the US-based cleric Turkey accuses of orchestrating a failed coup in July.

Justice minister Bekir Bozdag said the prison personnel and guards were temporarily suspended to remove individuals linked to cleric Fethullah Gulen in Turkish prisons.

He said they could be sacked if concrete links were found.

Turkey also ordered the closure of 20 television and radio stations, including one that airs children's programmes, on charges they spread "terrorist propaganda".

The move added to fears that emergency rule is being used to stifle the media.

President Tayyip Erdogan has said he wants a three-month state of emergency, which was imposed after the coup attempt, to be prolonged past October so authorities can eradicate the threat posed by a religious movement blamed for the attempt, as well as Kurdish militants who have waged a 32-year insurgency.

The banned channels are owned or operated by Kurds or the Alevi religious minority, according to Hamza Aktan, news editor at IMC TV, a news broadcaster slated for closure.

He cited a copy of the decision obtained by his channel, which was based on powers given the government in a decree issued in July.

"This has nothing to do with the coup. It is an effort to silence the last independent media covering the Kurdish issue and violations committed by the state," Mr Aktan told Reuters.

IMC has aired reports looking at security forces' conduct during 14 months of military operations against the outlawed Kurdistan Workers Party (PKK) that has killed thousands.

Among the 12 shuttered television channels are Govend TV, which plays folk music, and Zarok TV, which airs Kurdish-language children's cartoons.

The decision also shut 11 radio stations for harming national security, Mr Aktan said.

"Turkey is targeting a wide swath of cultural and political expression by shuttering minority broadcasters," Robert Mahoney of the Committee to Protect Journalists said.

"When the government sees even children's programming as a threat to national security, it is clearly abusing its emergency powers."

Mr Erdogan argues the state of emergency is helping authorities swiftly root out supporters of the military uprising by bypassing parliament to enact laws and suspend rights.

Turkey blames Gulen for masterminding the coup in which 240 soldiers, police and civilians were killed trying to stop rogue troops who had commandeered fighter jets and tanks to bomb parliament and shoot protesters.

Another 100 people behind the putsch were killed.

About 100,000 state employees suspected of links with the Gulen movement have been purged, and 32,000 people are in jail for their alleged role in the coup. Gulen denies involvement.

Authorities have also targeted the media, arresting dozens of members of the press to make Turkey the world's biggest jailer of journalists and shutting down scores of media outlets.