KINSHSASA, Oct 29 (Reuters) - Congolese police killed two people when they opened fire to disperse rioting supporters of presidential candidate Jean-Pierre Bemba during voting in the north of the country on Sunday, an official said. The police fired in the air after Bemba's supporters destroyed a polling station when they discovered alleged ballot stuffing in favour of his rival, incumbent President Joseph Kabila, said Yves Mobando, governor of Equateur province. "Two people were killed when the police opened fire to disperse the crowds," Mobando told Reuters. He said people were killed by stray bullets in the shooting in the town of Bumba, 800 km (500 miles) from Kinshasa. "The polling station was destroyed and a pro-Kabila radio station was attacked when the MLC supporters said there were already votes for Kabila in the ballot box before voting, " he said. The MLC is Bemba's party. The governor said the official election commission denied there had been stuffing of ballot boxes. In Sunday's election, Kabila and Bemba are contesting control of Democratic Republic of Congo, a vast central African country rich in minerals but devastated by decades of violence and corrupt government. The presidential run-off is accompanied by provincial elections. The polls are the first democratic vote for more than 40 years in the former Belgian colony.