Turkish prosecutors are seeking up to 43 years in jail for journalists from leading opposition newspaper Cumhuriyet on charges of supporting a terrorist organisation and targeting President Tayyip Erdogan through asymmetric war methods, Reuters reported on April 5.

The left-leaning Cumhuriyet is one of Turkey’s oldest newspapers with a daily circulation of around 40,000.

The indictment named 19 journalists, of whom 12 have already been detained, Reuters said.

According to the 324-page indictment, seen by the news service, Cumhuriyet had effectively been "taken over by the network of U.S.-based cleric Fethullah Gulen, and used to veil the actions of terrorist groups".

“Cumhuriyet started an intense perception operation targeting the government and president of the republic through asymmetric war methods," added the indictment.

The detained journalists and executives of Cumhuriyet had conducted several telephone conversations with the Gulenists, according to the document.

Can Dundar, the newspaper’s former editor, is accused of revealing state secrets involving Turkey’s operations in Syria. Dundar had obtained false information regarding the Syria operations from supporters of Gulen, the indictment said. Dundar currently lives in Germany.

The government says Fethullah Gulen and his supporters were behind the failed coup attempt last year that left more than 200 people dead. Many Turks have no sympathy for the Gulenists. Gulen-affiliated prosecutors and judges controlled the country’s judicial system and police force. They are said to have sent scores of people, including journalists and military officers, to prison on false charges and faked evidence.

Some suspects in the case against the newspaper were also accused of serving the interests of the Kurdistan Workers’ Party (PKK) and of the far-leftist DHKP/C.

In the wake of the botched putsch, Ankara launched a massive crackdown on the Gulenists, purging more than 100,000 people from their public duties.

The government says supporters of Gulen had infiltrated the judiciary, the police, the military and other key institutions to establish their own “parallel state”.

Dozens of media outlets deemed to be supportive of Gulen have been closed.

More than 40,000 people have also been arrested in the purge.

A state of emergency has been in place since last July.

The government has vowed to root out all allies of the US-based cleric from state and private institutions.

Against this backdrop, April 16 will see a referendum on Turkey switching to a constitutional system that critics say would put in place a strongman presidency with few checks and balances on its power.