Nigeria's electoral commission has announced a six-week postponement to the 14 February presidential election, citing fears over security and the Boko Haram insurgency.
The chairman of the Independent National Electoral Commission (INEC) Attahiru Jega said security chiefs advised a delay as troops would not be available because of operations against the militants.
"If the security of personnel, voters, election observers and election materials cannot be guaranteed, the lives of innocent young men and women and the prospect of free, fair and credible elections will be greatly jeopardised," he told reporters.
The election will now be scheduled for 28 March.
Earlier, Nigeria and its four neighbouring nations pledged to deploy 8,700 troops, police and civilians as part of a regional effort to fight Boko Haram militants.
"The representatives of Benin, Cameroon, Niger, Nigeria and Chad have announced contributions totalling 8,700 military personnel, police and civilians," the countries said in a statement after a meeting in Cameroon's capital Yaounde.
The announcement came out of a three-day summit focused on organising the force that will battle the Islamist militants, who are engaged in a worsening six-year insurgency centred in northeastern Nigeria.
However, it may be some time before the multi-national effort goes into action, as nations will continue in coming days to thrash out the details of each government's contribution as well as the budget.
Boko Haram's attacks have increasingly spilled over from Nigeria into neighbouring nations.
Their first major assault in Niger on Friday triggered a forceful response from Chadian and Nigerien troops.
Niger's defence minister reported that 109 of the Islamists were killed in the fighting, along with four soldiers and a civilian. Seventeen other troops were wounded.
