Turkish prosecutors are investigating people who have alleged on social media that a July 15 coup attempt was a hoax carried out by the government, the country's justice minister said.

Bekir Bozdag's comments on Sunday reflected what some critics say are increasing restrictions on expression in the wake of the failed rebellion by some military forces.

Meanwhile, Education Minister Ismet Yilmaz said Turkey also plans to hire more than 20,000 teachers to replace those who have been fired in a purge of suspected coup plotters in schools and other institutions.

The new teachers will replace state educators who have been dismissed as well as teachers in private schools with alleged links to Fethullah Gulen, a US-based businessman and cleric who has denied accusations that he directed the coup attempt that killed more than 250 people.

In other crackdown measures, Turkey has disbanded the presidential guard after already detaining nearly 300 unit members suspected of plotting against President Recep Tayyip Erdogan, and authorities detained Muhammet Sait Gulen, a nephew of the cleric who lives in self-imposed exile in Pennsylvania.

READ MORE: Turkey detains top Gulen aide after coup attempt

Justice Minister Bekir Bozdag said in an interview with Turkey's Kanal 7 television station on Sunday that anyone who suggests the coup attempt was staged most likely had a role in the insurrection, which was defeated by loyalist forces and pro-government protesters.

'Most are losers'

There has been some internet speculation that Erdogan engineered the unrest in order to rally support and thereby increase his power, a conspiracy theory rejected by the government and most commentators on Turkey's recent turbulence.

"Just look at the people who are saying on social media that this was theatre. Public prosecutors are already investigating them. Most of them are losers who think it is an honour to die for Fethullah Gulen's command," Bozdag said.

Turkey has declared a three-month state of emergency to restore security following the coup attempt, granting Erdogan the power to impose decrees without parliamentary approval.

More than 13,000 people, including nearly 9,000 soldiers, 2,100 judges and prosecutors and 1,485 police, have been detained, according to the president.

READ MORE: Fear grows as Turkey introduces state of emergency

In addition, Erdogan said, the government has closed and seized the assets of 15 universities, 934 other schools, 109 student dormitories, 19 unions and 35 medical institutions as well as numerous other associations and foundations suspected of links to Gulen's movement.

Turkey wants the United States to extradite Gulen. US President Barack Obama has said there is a legal process for extradition and has encouraged Turkey to present evidence.