Deputies have been appointed to replace the mayors after they were found supporting PKK, considered a terrorist group by Turkey, the US and EU, an Interior Ministry statement said.
Turkey's Interior Ministry said on Monday it dismissed three mayors in eastern Turkey for supporting terrorism.
According to a statement by the ministry, the mayors of Diyarbakir, Mardin and Van provinces – Adnan Selcuk Mizrakli, Ahmet Turk and Bedia Ozgokce Ertan – respectively have been suspended.
It added the mayors already had active 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.
Turkey’s vice president said in the struggle for democracy, the Turkish state was bound to take action against municipalities that supported terrorism and their leaders.
“Judicial and administrative investigations determined that municipal funds [in three cities] were being used in favour of a bloody terrorist organization, and necessary actions have been taken,” said Fuat Oktay on Twitter.
“The will of the nation can never be left under the hand of terror,” he added.
All mayors are from opposition HDP.
"The municipalities that we won on March 31 are being reassigned to trustees. It is being done on completely fabricated grounds,” HDP spokesman Saruhan Oluc said in a statement criticising the dismissal of three mayors.
The state-appointed governors of the provinces will temporarily replace dismissed mayors.
In its 30-year terror campaign against the Turkish state more than 40,000 people, including women and children, have been killed.
Turkey, the US and the EU recognise the PKK as a terrorist organisation.