A total of 418 suspects were arrested across Turkey including in southeastern Diyarbakır, Mardin and eastern Van provinces, Turkey's Interior Ministry said in a statement.
Operations are ongoing in the region, it added.
Also on Monday, the mayors of Diyarbakır, Van and Mardin provinces were replaced by the Interior Ministry over terrorism charges.
According to an official statement by the ministry, the mayors of Diyarbakır, Mardin and Van provinces — Adnan Selçu Mızraklı, Ahmet Türk and Bedia Özgökçe Ertan, respectively — have been suspended.
It added that the mayors already had ongoing cases against them in which they were accused of crimes such as establishing or spreading propaganda for a terror group or else just being a member.
All three mayors are from the opposition Peoples' Democratic Party (HDP), a party Turkey's government has accused of having links to the PKK terror group.
The state-appointed governors of the provinces will temporarily replace dismissed mayors.
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 deaths of nearly 40,000 people, including many women, children and infants.