Lagos, Nigeria (CNN) -- Nigeria's national security adviser has resigned from his post in order to run in the 2011 presidential election, he told CNN on Sunday.
In announcing his bid for the presidency, Gen. Aliyu Gusau will compete against President Goodluck Jonathan, who appointed Gusau to his national security post earlier this year to help quell religious clashes in the city of Jos.
Gusau is one of four main contenders from the country's north who announced Friday that they would put forth a single candidate to challenge Jonathan in next month's primaries for the People's Democratic Party.
Gusau's announcement comes a day after Jonathan formally declared that he will run in the 2011 elections.
"I have decided to humbly offer myself as a candidate in the presidential primaries of our party, the great PDP (People's Democratic Party)," he said Saturday.
Under Nigerian "zoning" rules, power must shift to different regions and ethnic groups every eight years.
Jonathan -- who is from the Niger Delta, in the south -- was part of the joint ticket of the late President Umaru Yar'Adua, who was from the north.
Yar'Adua's death in May, after a long illness, upset the order of the zoning. Yar'Adua was elected in 2007 and his southern replacement threatened to halt the north's turn at holding power.
Under an agreement with the four contenders from the north, Gusau will challenge Jonathan and the bloc will support his bid to try to win the election in favor of the north.
The challenge has the potential to split the ruling party when primaries are scheduled to be held between October 18 and 20. However, Nigeria's Independent National Electoral Commission indicated in a communique Sunday that it could extend the timeline for the election.
CNN's Christian Purefoy contributed to this report.