Nigeria on Friday announced the recapture of Boko Haram's headquarters, on the eve of a knife-edge vote at which President Goodluck Jonathan is eyeing re-election against a stiff opposition challenge.
The military hailed the claimed victory in Gwoza as a crushing defeat for the rebels, whose six-year insurgency has left more than 13,000 dead and which Jonathan had seemingly been unable to stop.
The latest reported military success was announced in a capital that appeared largely empty, as Abuja's residents cleared out of the city centre before the closely-fought vote, with both sides promising victory and widespread fears of post-election unrest.
Boko Haram has dominated the campaign, with Jonathan's record on security attacked by the All Progressives Congress (APC) candidate, former military ruler Muhammadu Buhari.
Buhari said as campaigning ended on Thursday that he would make rebuilding the army and security agencies a "top priority" of his administration.
"I will ensure that never again will terrorists find a safe haven in Nigeria," he added, vowing also to reunite the 219 schoolgirls held hostage by the group since last April with their families.
Reports have suggested that the teenagers, whose abduction from the remote town of Chibok in Borno state caused global outrage, were being held in Gwoza.
But two locals told AFP that there was no sign of the girls in the town, which Boko Haram declared part of a caliphate last August and renamed "Darul Hikma" in Arabic, meaning "House of Wisdom".
- Women killed -
One man who was forcibly conscripted into the militant ranks claimed that Boko Haram leader Abubakar Shekau personally ordered his fighters to kill women in Gwoza before they retreated.
"They gathered the women who were in large number and opened fire on them," said Usman Ali, a 35-year-old farmer who later managed to escape, in an account supported by another local man.
The account mirrors similar testimony from the town of Bama, which was recaptured earlier this month.
Nigeria's defence spokesman Chris Olukolade said a number of dead bodies had been found in a deep well in Gwoza but did not elaborate.
The recapture of Gwoza leaves just a handful of places in the northeast under rebel control, according to Abuja, which has talked of the "final onslaught" against the militants.
Fears about security persist after Shekau vowed to disrupt the vote, as opposition loyalists pledged to take to the streets if the polls are marred by foul play.
"If they rig, there is a problem," said Abdullahi Usman Chitta Michika, referring to the ruling Peoples Democratic Party (PDP).
"We will go out and we will not come back home. We will sleep in the roads. We are going to contest seriously," the 31-year-old told AFP at a market on the outskirts of Abuja.
But if the president wins in a vote deemed free and fair, "I will be the first person to congratulate Mr Jonathan", Michika said.
Vehicle restrictions will be in place from when polling stations open at 8:00 am (0700 GMT) on Saturday, with a strong police and security service presence.
Some 1,000 people were killed in clashes after the last election in 2011 when Jonathan defeated Buhari and there are fears of a repeat this time round.
- Call for calm -
Both candidates on Thursday renewed their pledge to non-violence and on Friday Jonathan called for Nigerians to vote "en masse" but "peacefully".
"The eyes of the entire world are on us," he said in a televised speech, adding that a well-observed poll would be a "fitting example of political maturity for other emerging democracies".
Nigeria is Africa's most populous nation, leading economy and top oil producer and its election is being closely watched across Africa and in major Western capitals.
US President Barack Obama this week called on Nigerians to reject violence and instead seize a "historic opportunity" for progress.
The military operations against Boko Haram involving Nigeria, Niger and Chad, with support from Cameroon, were given as a reason for the February 14 election to be postponed to this Saturday on security grounds.
Troops deployed to the restive northeast would be unable to provide security nationwide, Nigeria's national security advisor Sambo Dasuki said at the time.
But the APC, among others, claimed the postponement was politically motivated, allowing Jonathan to claw back ground lost to the main opposition.
There will be similar claims that the recapture of Gwoza was announced to seek last-minute political capital for Jonathan in Saturday's election.