Nigeria Poll: Those Who Refuse to Be Forgotten

Nigeria's two main presidential candidates have signed an agreement not to stoke tensions ahead of Saturday's tightly contested elections.

The election is being seen as the closest race in the country's history, with President Goodluck Jonathan facing a strong challenge from former military ruler Muhammadu Buhari.

Nigeria has a history of election-related unrest and both candidates appeared keen to prevent a repeat of 2011, when around 800 people were killed in clashes after the results were announced.

This time round, fears of Boko Haram attacks at vulnerable targets, including polling stations, have seen unprecedented calls for vigilance from the security services.

Land and sea borders have now been closed as part of stringent security measures that also include an eight-hour restriction on movement when polling stations are opened.

Sky's Special Correspondent Alex Crawford is in the Nigerian capital Abuja covering the crunch vote.

In her latest report, she speaks to relatives of some of the girls kidnapped in Chibok by Boko Haram militants almost a year ago who refuse to be forgotten in the race for political power.