Bloemfontein - A pilot and his assistant were killed when their helicopter crashed in Clocolan, Free State police said on Thursday.

Colonel Thandi Mbambo said the two men, one from Winburg and other from Limpopo were busy searching for their buffaloes with a light helicopter at Bigstok farm the district of Clocolan on Wednesday.

"The buffaloes were on the mountain on the same farm. It is alleged that the victim from Winburg was a pilot while the one from Limpopo was his assistant," Mbambo said.

"The pilot did not realize the electric cable because they were both concentrating on the ground as they were searching for those buffaloes on the mountains, and they accidentally bumped against the electric cable. The helicopter fell on the ground and was badly damaged. Unfortunately the victims died on the scene."

She said the Civil Aviation SA and other role players were called to the scene.