By Halife Yalcinkaya, Serhat Zafer, Bilal Altiok, Meltem Yilmaz, Emrah Yasar, and Salih Baran

ANKARA/EDIRNE/ESKISEHIR/TRABZON/BURDUR, Turkey

Turkish forces arrested 21 terror suspects, security sources said Saturday.

The suspects belonged to Fetullah Terror Organization (FETO), PKK, and al-Nusra terrorist organizations.

Eleven PKK suspects were rounded up in capital Ankara after the public prosecutor's office issued arrest warrants for 19 people, said a source, who requested anonymity due to restrictions on speaking to the media.

In its more than 30-year terror campaign against Turkey, the PKK -- listed as a terrorist organization by Turkey, the U.S. and the EU -- has been responsible for the death of some 40,000 people, including women and children.

In a separate operation, four suspects were arrested over links to FETO while they were trying to escape to Greece through the northwestern Turkish province of Edirne.

A suspect, who was wanted for being the "chief" of FETO-linked university graduates, was arrested. He was also accused of infiltrating FETO members into the Turkish air force.

In another operation, a husband and wife were detained for suspected links to FETO in the Black Sea province of Trabzon.

In the southwestern province of Burdur, a wanted suspect was arrested during an anti-terror operation.

FETO and its U.S.-based leader Fetullah Gulen orchestrated the defeated coup attempt of July 15, 2016, which left 250 people martyred and nearly 2,200 injured.

Two individuals were also remanded in Burdur and central Sivas province over links to al-Nusra.

Turkey designates al-Nusra as a terrorist organization and continues to fight against the Al Qaeda-linked group, both inside and outside the country.