A group of unknown people have attacked two bus, a van and a number of local offices of the main opposition Republican Peoples’ Party (CHP) in Antalya.

According to Haberdar news portal on Saturday, the vehicles and front sides of some CHP offices in Antalya’s central district of Muratpasa was painted with black spray.

The attack mostly targeted huge ‘No’ banners on buses and the offices.

Turks are set to cast their votes in a referendum on whether to approve an executive presidency that will, in case of a Yes result, give sweeping power to President Recep Tayyip Erdogan while weakening Parliament, on Sunday, Apr 16.