Turkish prosecutors ordered the arrests of 532 suspects with connections to a Muslim cleric allegedly behind a 2016 attempted coup, according to a report on Monday by state-owned Anadolu news agency. These 532 suspects include 459 on-duty military personnel.

In 2016 there was a failed coup attempt by rogue soldiers to overthrow President Recep Tayyip Erdoğan’s government. This led to crackdowns and mass arrests, resulting in more than 250 deaths. Ankara accused the followers of exiled Muslim cleric Fethullah Gülen of plotting the coup. Gülen, however, denied any involvement.

Last June a Turkish court sentenced US consulate employee Metin Topuz to eight years and nine months for aiding a 2016 coup attempt. The US Embassy denounced the sentencing. In March Turkish security forces arrested 203 soldiers in nationwide raids targeting military personnel accused of links to Gülen.

The announced investigation is being conducted in 62 provinces, as well as the Turkish Republic of Northern Cyprus. It was initiated by prosecutors in Istanbul and western Izmir province. The 459 on-duty military personnel suspects include four colonels, one lieutenant colonel, nine majors and 24 captains.

The operation is said to be against the infiltration of the Fetullah Terrorist Organization (FETO) in the Turkish Armed Forces. Suspects were reportedly found to be involved in intra-organizational communication through payphones or fixed lines.