A main opposition party rejected a proposed boycott of weekend presidential elections, saying Thursday that even though it was worried about fraud, opting out would only help the governing party.

The All Nigeria People's Party led by presidential candidate Gen. Muhammadu Buhari was among 18 opposition parties that had threatened in a joint statement earlier this week to boycott unless the government postponed Saturday's vote pending the creation of a new electoral commission.

But "we shall not boycott and we will participate fully," a party leader, Edwin Ume Ezeoke, told reporters in the capital, Abuja.

He said boycotting Saturday's vote would only bolster the position of the ruling party, which the main opposition groups accuse of rigging an April 14 vote for state officers. The governing party was declared winner of more than two-thirds of the 36 governors races held April 14.

The joint opposition statement also had demanded the April 14 results be tossed out. The government rejected all the demands.

Opposition party delegates were still scheduled to meet to consider a boycott, but the possibility of presenting a united front was shattered by Ezeoke's announcement.

Saturday's vote is meant to set up the first transfer of power between elected governments in Africa's most-populous nation. The run-up to the vote has been chaotic and bloody.

At least 21 people died in political violence during the April 14 vote.

A top opposition candidate, Vice President Atiku Abubakar, was ordered back on the ballot this week by the Supreme Court. The electoral commission had disqualified him based on corruption allegations, but bowed to the court -- without explaining how his name would be added to the 61 million ballots with only days to go.

On Wednesday, Nigerian soldiers killed at least 25 suspected Islamic militants Wednesday while battling extremists who attacked a police station a day earlier in the northern city of Kano, a military spokesman said.

Following the attack on the police station Tuesday that killed a dozen officers and a policeman's wife, hundreds of soldiers and police surrounded the neighborhood Wednesday and drove the militants out, military officials said.

Residents flooded from the area to escape the battle, parents holding their children close while hurrying down dusty streets. People reported seeing numerous bodies in the streets, but offered no specific count.

Col. Ayo Olaniyan, an army spokesman, said at least 25 of the Islamic militants had been killed. He didn't say whether there were any government casualties.

Olaniyan called the militants self-styled "Taliban" extremists who crossed into Nigeria from neighboring Chad.

The fighting appeared to stem from a dispute among rival Islamic factions in northern Nigeria, which shares a long, largely unprotected border with Chad that many people living in the desert region ignore.

Kano is one of 12 northern Nigerian states where Islamic law is practiced, and groups have clashed periodically over its proper implementation. Religious hard-liners, who make up a small minority, want a stricter interpretation that further separates men and women.

Violence has risen during the approach of elections in Nigeria, whose 140 million people are roughly split between Muslims in the north and Christians and animists in the south.