U.S. Secretary of State John Kerry plans to meet with the leading candidates in Nigeria’s upcoming presidential election, the State Department announced. Officials said that Kerry is to arrive in Nigeria Sunday and hold separate talks with Nigerian President Goodluck Jonathan and former army Gen. Muhammadu Buharim, Jonathan's leading challenger.

Jonathan’s administration has been accused of allowing militants to slaughter civilians in the country’s northern region, opponents say, because it is largely made up of support for the opposition party.

Kerry will be the first chief American diplomat to visit Nigeria since 2012, the Associated Press reported, and the secretary of state is only expected to stop in the West African nation’s capital for a few hours. During his visit, Kerry will appeal to both candidates to accept the result of the Feb. 14 election and is expected to instruct each candidate's supporters to refrain from violence, State Department officials said. Jonathan's disputed 2011 election victory was followed by riots in the north that killed an estimated 800 people.

"He’s only going to be there a short period of time. But it’s not a situation where we’re hosting one candidate or another in our country or he’s meeting to support one candidate or another," State Department spokeswoman Jen Psaki told the regular press briefing Friday in response to a question.

Nigeria's hotly contested elections are expected to be particularly contentious because of recent attacks by terrorist group Boko Haram, which has ravaged the country’s northeastern region since 2009 when it announced a campaign to create an Islamic caliphate. The group, which has pledged allegiance to the Islamic State, stepped up attacks in 2014. Since 2009, 15,000 people have been slaughtered. During its January offensive this year, the group killed more than 2,300 people and displaced more than 1 million from their homes, according to data compiled by the Armed Conflict Location and Event Data Project, a research effort mostly focusing on African conflict with ties to the Robert S. Strauss Center for International Security and Law at the University of Texas at Austin.

Boko Haram will be an important topic of Kerry's discussions, State Department officials said, the AP reported.

In December, Nigeria canceled the last stage of U.S. training of a Nigerian army battalion, a reflection of strained counterterrorism relations between the two governments.