"Our presidents will likely meet soon," she was quoted by Nigerian newspaper ThisDay as saying. "I will leave that announcement to the president of the United States and the president of Nigeria."

Sherman led a delegation to Abuja for a bilateral meeting that started Thursday. She said she carried with her a letter to Jonathan from Obama expressing his appreciation for Nigeria's regional and international leadership.

The Nigerian newspaper said there was a general sense of frustration that Nigeria was snubbed by Obama when he toured Africa in June.

Jonathan is struggling to maintain a sense of national security at home. Militant group Boko Haram claimed responsibility for a weekend attack on mosques in the northern Nigerian state of Borno. At least 60 people were killed in the attack.

Sherman said she was committed to Nigeria "as it moves forward to meet all the challenges before it."