Turkish authorities have detained 42 university staff

Turkish state media reported Monday that authorities have detained 42 university staff and issued a total of 72 arrest warrants as part of an investigation into the group blamed for last year's failed coup and for suspected links to US-based Muslim cleric Fethullah Gulen.

One of those detained was academic Koray Caliskan, main opposition People's Republican Party (CHP) lawmaker Oguz Kaan Salici said on Twitter.

Ankara accuses Gulen of ordering the failed plot to oust President Recep Tayyip Erdogan but Gulen strongly denies the charges.

The staff from Bogazici and Medeniyet universities are accused of using the encrypted messaging app, ByLock, which Ankara claims was especially created for Gulen supporters, Anadolu reported.

The authorities issued detention warrants for eight staff from Bogazici University and 64 staff from Medeniyet University including 19 of its professors from the medical school, Dogan news agency said.

Meanwhile, the Ankara chief public prosecutor issued arrest warrants for 43 people including six staff currently working at the prime minister's office and related institutions, Anadolu reported Monday.

The agency said "some" had been detained during an operation after it was suspected they used Bylock, which authorities have frequently cited by as "evidence" of alleged links to Gulen.

Over 50,000 people have been arrested in connection with the failed putsch while more than 100,000 people have been dismissed from the public sector including teachers, judges, police and soldiers under the state of emergency imposed after the coup bid.

Although activists and Western governments have criticized the crackdown, the government insists it is necessary to tackle the threat they say is posed by the Gulen movement.

Related: Turkey jails more journalists than any other nation. Those in detention are all terrorists, Erdogan says.