ANKARA (Reuters) - Turkish police detained dozens of people on Thursday in an investigation of student dormitories suspected of ties to the network of a U.S.-based cleric accused by Ankara of masterminding July’s failed coup, state-run Anadolu agency said.

Turkey has jailed some 36,000 people pending trial and has suspended or dismissed more than 100,000 state personnel over links to the cleric, Fethullah Gulen, who lives in self-imposed exile in the United States. He denies involvement in the putsch.

Arrest warrants were issued for 136 people in the dormitories’ operation across 20 provinces, Anadolu said.

It said 35 people had so far been held and 70 suspects were found to have used Bylock, a smartphone messaging app which Ankara says was used by Gulen adherents as a communication tool.

The warrants targeted administrators of 29 dormitories which were closed down with an official decree, and representatives of companies linked to the halls of residence, Anadolu said.

In a separate investigation, Anadolu said arrest warrants had been issued in 16 different provinces for 58 people suspected of being senior figures in Gulen’s network. Police have been carrying out searches since the early morning.

Among those sought are police officers, research assistants, teachers and engineers, Anadolu said.

The crackdown has covered a wide range of professions and alarmed human rights groups as well as Turkey’s Western allies, which fear President Tayyip Erdogan is using it as a pretext to curtail dissent in the nation of 79 million people.

The government says it is necessary to stamp out the influence of Gulen’s network, which it refers to as the “Gulenist Terror Organization”, or “FETO”. Erdogan’s opponents say the purges go far beyond a crackdown on suspected Gulenists.

Last month, a government official told Reuters that Turkish authorities were investigating foster families for suspected ties to Gulen and may remove children from homes if their guardians are found to be supporters of the putsch. [nL8N1DT3JH

Gulen’s “Hizmet” movement runs some 2,000 educational establishments in 160 countries, from Afghanistan to the United States, along with private educational institutions in Turkey.