FILE PHOTO: U.S.-based Turkish cleric Fethullah Gulen at his home in Saylorsburg, Pennsylvania, U.S. July 10, 2017. REUTERS/Charles Mostoller/File Photo

ISTANBUL (Reuters) - Turkish authorities on Tuesday ordered the detention of 168 people, including military personnel, with suspected links to the network that Ankara says orchestrated a 2016 coup attempt.

Ankara has cracked down on suspected followers of Fethullah Gulen, a U.S.-based Muslim cleric, since the coup attempt in which some 250 people were killed. Operations against the network are still routine.

Istanbul prosecutor’s office said it ordered the detention of two civilians and 52 military personnel, including two retired colonels, a lieutenant colonel on active duty and two former majors who had already been expelled from the military. More than half of them were detained by early Tuesday.

Istanbul police said they had detained 15 of the 27 people for whom the prosecutors issued warrants in a separate investigation, over the suspects’ use of ByLock, an encrypted messaging app used by Gulen’s network.

In the central province of Konya, state-owned Anadolu news agency said prosecutors issued detention warrants for 50 people. Anadolu also said that 36 soldiers were ordered detained by Ankara prosecutors, in addition to one civilian.

Gulen has lived in self-imposed exile in Pennsylvania since 1999. He has denied any involvement in the coup attempt.

In the three-year purge since the coup attempt, more than 77,000 people have been jailed pending trial and about 150,000 civil servants, military personnel and others have been sacked or suspended from their jobs.

Turkey’s Western allies and rights groups have criticized the scale of the crackdown, saying President Tayyip Erdogan has used the abortive coup as a pretext to quash dissent.

Ankara has defended the measures as a necessary response to the scale of the security threat which Turkey faces, vowing to eradicate Gulen’s network.