Turkish police on Tuesday detained nearly 140 people in nationwide raids over alleged links to the group blamed for the 2016 failed coup, state media reported.

Prosecutors across the country, including in Istanbul and Ankara, issued 267 arrest warrants, according to state news agency Anadolu, as part of different investigations into followers of US-based Muslim preacher Fethullah Gulen.

Police launched operations in 24 provinces including Izmir and Mugla on the Aegean coast and Ordu and Zonguldak on the Black Sea.

By late Tuesday morning, 137 suspects had been detained including 55 in Istanbul as raids continued to capture others, Anadolu reported.

Ankara accuses Gulen of ordering the attempted overthrow of President Recep Tayyip Erdogan on July 15, 2016, but he strongly denies the claims.

Gulen, who lives in self-imposed exile in Pennsylvania, and his followers stress that their movement is peaceful, promoting Islam and education.

The probes include one led by the Istanbul public prosecutor into the movement — referred to as the “Fethullah Terrorist Organisation” (FETO) — and businesses linked to Gulen. The prosecutor issued 96 detention warrants, Anadolu said.

Meanwhile, prosecutors in the Turkish capital sought the arrest of 48 individuals over their alleged use of an encrypted messaging application called ByLock, which Turkish officials claim was especially created for Gulen supporters.

So far, 35 people including engineers, civil servants and individuals working in the private education sector have been detained in Ankara, the agency reported.

The investigations that led to Tuesday's raids also focused on Gulen followers' presence and actions inside the military.

Some of the suspects wanted were soldiers on active duty or sacked military personnel.

Another 16 suspects were charged by an Istanbul court of “being a member of an armed terrorist organisation”, Anadolu reported on Tuesday.

Tens of thousands of people have been arrested over suspected Gulen links since 2016.

Despite criticism from activists and Ankara's Western allies expressing concern over the scale of the crackdown, the raids show no sign of slowing down.

Turkish officials insist that the operations are necessary to remove the “virus” that is the Gulen movement's infiltration of key Turkish institutions.