By Tim Cocks and Julia Payne
LAGOS (Reuters) - Nigeria's presidential challenger Muhammadu Buhari pledged to cheering crowds in opposition stronghold Lagos that he would tackle the country's three greatest ills -- insecurity, inequality and corruption.
Africa's most populous nation votes on Feb. 14 for either Buhari of the All Progressives Congress or President Goodluck Jonathan of the ruling People's Democratic Party.
It will be the former military ruler's fourth attempt at the presidency, but this time he enjoys much broader support than before.
As head of the military government between 1983 and 1985 he was seen as tough on corruption and in his dealings with rebellions and armed criminals.
The race is expected to be the most closely fought since the end of military rule in 1999, and the majority ethnic Yoruba southwestern states, which voted for Jonathan last time, are seen as crucial swing states.
Civilian rule has since been dominated by the PDP, so its loss at the ballot box would signal an unprecedented shake up of the country's fledgling democracy.
Jonathan was earlier viewed as an easy victor but the momentum has shifted to the opposition in the last few months, with Buhari drawing appeal from a mix of middle class intellectuals fed up with corruption, jobless youths, and growing numbers from all walks of life worried about insecurity.
"The APC has identified three fundamental problems ... One, insecurity, two, concentration of the economy (in few hands) and three, bribery and corruption," Buhari told thousands of supporters in a packed stadium, many of them wearing T-shirts or traditional, vibrantly colored robes depicting his face and that of running mate Yemi Osinbajo.
Many supporters were bussed to the venue in APC decorated vehicles also with the beaming faces of the duo splashed over them.
Before the candidate's speech, each speaker yelled "APC, APC!" and waved a rustic straw broom, the party's symbol, while a plane flew overhead dragging a banner with the words "I have decided to vote for Buhari".
Buhari, a northern Muslim, said he would first tackle the insurgency in the northeast of the country, where Sunni jihadist group Boko Haram has killed thousands in its attempt to carve out an Islamic state in Africa's biggest economy.
Jonathan has been criticized for not doing enough to protect civilians from Boko Haram and for failing to defeat the insurgents. It is a sign of how under siege Nigerians feel that so many of them regard a military strongman who trampled over civil liberties as the answer to their problems.
"He's a military man with experience of these tough situations. Only a man like that can tackle Boko Haram," said Umar Ali, a Lagos food trader originally from Bama, one of the towns worst affected by the insurgency. His brother was shot dead in a militant attack there three weeks ago.
Boko Haram now controls swathes of territory, mostly in Borno state, leading to much criticism of Jonathan as commander in chief of the army, which seems unable to quash the group.
The president, a Christian and former zoology lecturer from the oil producing Niger Delta, blames his predecessors for starving the military of funds for fear it might stage a coup.
Buhari said he would focus on increasing the number of jobs for young people at a time of high youth unemployment, and that his administration would reinvest the money saved from cracking down on corruption into revamping education.
He blamed Nigeria's lack of a national railway, airline and shipping lines and particularly the unreliable power grid on years of graft.
Jonathan has achieved the sell-off of the moribund state power company, but the impacts of this success have yet to be felt on the grid.
(Editing by Giles Elgood)