Turkish Prime Minister Recep Tayyip Erdogan says he believes hundreds of military officers and others convicted of plotting to overthrow his government should be retried.
His senior adviser recently suggested that the officers had been framed by police and prosecutors.
Hundreds of people were jailed in 2012 and 2013 in two high-profile cases, the BBC reports.
In December last year, some of those prosecutors also ordered the arrest of a number of the Mr Erdogan's allies on corruption charges.
Three ministers resigned after their sons were arrested, along with dozens of others, over alleged wrongdoing in construction contracts and deals with Iran.
Mr Erdogan condemned the investigation as a "dirty plot".
