At least five Nigerian state governors who left the ruling party have joined the opposition - a move that could have a major impact on Nigerian politics.

The governors of Kano, Sokoto, Adamawa, Rivers and Kwara states said Tuesday they are joining the All Progressives Congress party, or APC.  

Initial reports said the governors of Niger and Jigawa states also would join, but the two governors issued denials.

State governors have great power in Nigeria, and the addition of the five governors effectively bolsters the APC's strength in parliament.  

It also positions the APC to mount a strong challenge to President Goodluck Jonathan and the ruling People's Democratic Party [PDP] in the 2015 elections.

The PDP has been in power for 15 years, but it has struggled with internal conflicts, especially since Jonathan's election in 2011.

Many northerners say Jonathan, a Christian from southern Nigeria, broke an unwritten rule that the presidency should rotate between the mainly Christian south and the mainly Muslim north.

Jonathan first became president after President Umaru Yar'Adua, a Muslim, died during his first term.

The breakaway governors defected from the PDP in August. They include both northern Muslims and southern Christians.