President Goodluck Jonathan. (File: AFP)
Washington - President Goodluck Jonathan is running against former military ruler Muhammadu Buhari in what looks set to be the closest presidential race since military rule ended in 1999.
The top US diplomat for Africa will travel to Nigeria to observe presidential elections, the State Department said Thursday, an unusual move for Washington that is closely monitoring the country's Islamist crisis.
Assistant Secretary for African Affairs Linda Thomas-Greenfield will lead an "official diplomatic observation mission" of the presidential and national assembly elections that take place Saturday, according to a statement.
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"This is the latest example of U.S. support for a credible, peaceful electoral process in Nigeria," the State Department said.
Thomas-Greenfield departs the US Friday for the capital Abuja and she may hold talks with officials while there.
Her visit to Nigeria is an unusual one for the US which rarely sends diplomats abroad to observe elections.
The US closely follows political developments in Nigeria partly due to the country's bloody Boko Haram uprising that has dragged on for years.
President Barack Obama on Monday asked Nigerians to vote in the country's elections, and appealed for calm against people who call for violence.
Campaigning ended Thursday night in Africa's demographic giant in a close race that has incumbent President Goodluck Jonathan, 57, squaring off against former General Muhammadu Buhari, 72.
US Secretary of State John Kerry visited Nigeria on January 25 in support of the elections that were first scheduled for February 14 before being rescheduled due to military operations against Boko Haram.
Kerry promised increased US support for the Nigerian army in its fight against the radical group.