Five key governors say they have defected to Nigeria's new coalition opposition in a blow to President Goodluck Jonathan's governing party and its chances for re-election in 2015.

The defectors include the powerful governors of oil-rich Rivers State in the mainly Christian south and Kano, the second most populous state in the predominantly Muslim north.

A statement posted Wednesday by the All Progressives Congress quoted the defectors' leader, Abubakar Kawu Baraje, a former ruling party chairman, as saying the dissidents agreed to a merger "to rescue our fledgling democracy."

Jonathan's party has governed the oil-rich nation since decades of military dictatorship ended in 1999.