Nigerian Senate candidate killed three days before election

Nigerians are due to elect their next president and lawmakers on Saturday. President Muhammadu Buhari is stepping down after serving the maximum two terms allowed by the constitution.

The three-man race to be his successor is seen as the most unpredictable in recent history and the run-up to the election has been marred by violence, a pattern seen in previous polls in Africa's most populous country.

Police confirmed the killing of Labour Party candidate Oyibo Chukwu, which came hours after the parties and presidential candidates signed a pledge to support a peaceful electoral process.

Chinwuba Ngwu, the Labour Party chairman in the Enugu South local government area, said Chukwu had been ambushed and killed as he travelled back from a campaign event.

"He was shot dead and then set ablaze in his vehicle with his driver and one of his boys," Ngwu said.

"It is a devastating development for us. We are suspecting political assassination because he is favoured to win the election," he said.

U.S. President Joe Biden earlier called for a peaceful, transparent election, urging parties and candidates to accept the results when they are published by the Independent National Electoral Commission (INEC).

"All Nigerians deserve this chance to choose their future — freely and fairly," Biden said in a statement.

"While the United States does not support any single candidate or party, we strongly support a peaceful and transparent process that reflects the will of the people of Nigeria."

The main candidates for president are former Lagos governor Bola Tinubu, 70, who represents the ruling party, former vice president Atiku Abubakar, 76, who represents the main opposition party that was in power from 1999 to 2015, and Peter Obi, 61, an anti-establishment candidate popular among many young voters.

Obi, an ethnic Igbo, is running on the Labour Party ticket. He is particularly popular in the Igbo heartland in southeastern Nigeria, which includes Enugu State, and this may have boosted the lesser known party's profile in the region.