Dozens of special forces personnel were arrested in Turkey Saturday in the latest development in a sweeping crackdown following the failed coup in the country that killed over 270 people, the state-run Anadolu news agency said.

Nearly 90 staff members were arrested after being identified by a commission established by the Special Forces Command following the July 15 coup, the agency reported.

The crackdown targets suspected followers of U.S.-based cleric Fethullah Gulen, who Ankara accuses of masterminding the coup attempt. Tens of thousands of employees in the military, police force, judiciary and throughout the public sector have been dismissed, detained or arrested.

Turkey has also been reforming its security apparatus in the aftermath of the failed coup, with the military being brought firmly under civilian authority in a series of governmental decrees following the declaration of a state of emergency.

Earlier on Saturday Prime Minister Binali Yildirim hosted a security summit of high-level government and military officials in Ankara. Those attending included the country's foreign, justice, interior and defense ministers, the chief of general staff and the heads of Turkey's national intelligence agency and the national police. No decisions were announced following the meeting.

As part of its anti-coup campaign, Ankara has been encouraging nightly anti-coup rallies throughout the country, with officials preparing for the grand finale to be held in Istanbul on Sunday.

The "Democracy and Martyrs' Rally" is meant to represent the unity of the country, with President Recep Tayyip Erdogan urging attendees to bring only the Turkish flag instead of party banners.

"There we will stand together as a single nation, a single flag, a single motherland, a single state, a single spirit," he said.

The event will be attended by the highest levels of Turkish leadership and two of Turkey's three opposition parties. The pro-Kurdish People's Democracy Party, or HDP, was not invited.

Anadolu news agency estimates that millions could attend the event.