United States President Barack Obama has offered strong support for Nigeria's new President, Muhammadu Buhari, saying he had a clear agenda for defeating the militant Islamist group Boko Haram and was working to root out corruption.

Obama was speaking on Monday as he greeted Buhari on his first visit to the White House since his election in March.

He said the two leaders would discuss ways to cooperate against the group, which has wreaked havoc in parts of the West African country.

Obama told reporters in the Oval Office that Buhari has integrity and "a very clear agenda in defeating Boko Haram extremists of all sorts inside his country".

Obama said the US hoped to partner with the African nation "so that Nigeria ends up being an anchor not only of prosperity and stability in the eastern part of the continent, but can also be an outstanding role model for developing countries around the world".

Nigeria is in the western part of the continent, and the White House said Obama had misspoken.

Boko Haram has carried out many attacks in northern Nigeria, most notably the kidnapping of 276 Nigerian school girls in April last year who are still missing.

The specific tactics Buhari will use against the group are still unknown, according to experts who study the region.

White House spokesman Josh Earnest said the US could offer intelligence to help the Nigerian efforts as well as support for communities hurt by the group.

Obama described Buhari's election as "an affirmation of Nigeria's commitment to democracy", and the visit is aimed at ushering in a new chapter in relations between the two countries.

US cooperation with Buhari's predecessor, Goodluck Jonathan, had virtually ground to a halt over issues including his refusal to investigate corruption and human rights abuses by the Nigerian military.

Buhari's move on July 13 to fire military chiefs appointed by Jonathan clears the way for more military cooperation, US officials say.

Since Buhari's election, Washington has committed $5 million in new support for a multi-national task force set up to fight Boko Haram. Obama did not signal whether he might send US troops to help train Nigerian forces.

Reuters - AP