The Latest: Nigeria delays presidential vote until Feb. 23 The Latest: Nigeria delays presidential election until Feb. 23 over 'challenges'

KANO, Nigeria -- The Latest on Nigeria's election (all times local):

2:50 a.m.

Nigeria's electoral commission says the presidential election is delayed until Feb. 23 over unspecified "challenges" amid reports that voting materials have not been delivered to all parts of the country.

Commission chairman Mahmood Yakubu spoke to reporters a little over five hours before polls were supposed to open in Africa's most populous country and largest democracy.

The commission promised more details at a 2 p.m. briefing in the capital, Abuja.

Yakubu said that "this was a difficult decision to take but necessary for successful delivery of the elections and the consolidation of our democracy."

In 2015, Nigeria delayed the election by six weeks over insecurity.