LIMA, Peru –  Peruvian officials say suspected Shining Path rebels killed two police officers and wounded a third in an ambush of a convoy transporting ballot boxes for Sunday’s regional and municipal elections.

Police say the attackers opened fire with assault rifles just before dawn Friday on four vehicles carrying 28 police officers near the town of Machente in the southeastern region of Ayacucho.

As much as one-fifth of the world’s cocaine is produced in the region known as the Apurimac and Ene river valley, and authorities say the Shining Path remnants operating there are principally drug traffickers.

Officials say this election campaign has been the most violent since 2000, the year then-President Alberto Fujimori fled into exile in a corruption scandal. Two mayoral candidates have been killed in gangland-style slayings this campaign.