An armed group has kidnapped nine politicians in southwestern Nigeria, and is demanding payment for allegedly helping the ruling party to rig the April elections.

Ruling party officials in Nigeria's Ondo state have denied having any agreement with the gang, while state officials say the kidnappers are criminals with whom the government will not negotiate.

The kidnappers seized 11 politicians in all at a gathering of the People's Democratic Party in Ondo state late Saturday. Nigerian newspapers say two of the men were released Monday.

The kidnappers are demanding a payment of about $4 million.

Reuters news agency Tuesday quoted a spokesman for the kidnappers as saying they would release photos of government officials meeting with gang members and supplying them with weapons.

International observers say Nigeria's April elections were badly marred by widespread and open vote-rigging. The European Union declared the elections "not credible." Opposition parties have challenged many of the results in court.

Some information for this report was provided by Reuters.