US Secretary of State John Kerry was due in Nigeria Sunday, just weeks away from closely fought elections overshadowed by fears about mounting Boko Haram violence and poll-related unrest.

US Secretary of State John Kerry was due in Nigeria Sunday, just weeks away from closely fought elections overshadowed by fears about mounting Boko Haram violence and poll-related unrest.

Kerry announced the trip on Friday at the World Economic Forum in Davos, Switzerland, where he spoke at length on the threat to the world from Islamist extremist groups, including Boko Haram.

But his visit was not expected to focus solely on the insurgency, Nigeria's handling of which has led to tensions between Abuja and Washington.

Instead, Kerry was understood to want to focus on the February 14 presidential and parliamentary elections, which are tipped to be the closest since Nigeria returned to civilian rule in 1999.

The United States has pressed for the elections to go ahead, despite the raging violence in Nigeria's far northeast that risks leaving hundreds of thousands of displaced people unable to vote.

This week, the country's national security adviser, Sambo Dasuki, called for polling to be delayed, as 30 million voter cards had yet to be distributed. But the electoral body maintained it was on track.