WASHINGTON (AP) _ State Department spokesman Nicholas Burns said Thursday it was ``outrageous and unfounded'' to suggest the United States was involved in a recent series of bombings in Nigeria.

He said U.S. Ambassador Walter Carrington would not give up his diplomatic immunity to appear at a hearing ``in a country that is dictatorial and has no rule of law.''

Nigeria's national police chief, Ibrahim Coomasie, wants to question Carrington about a recent series of bombings, which have killed at least 10 people. The Lagos authorities have suggested U.S. diplomats may have known about them in advance but have not produced any evidence linking embassy staff to the explosions.

``It would be foolhardy on our part'' for Carrington to waive immunity and appear, Burns said. ``It's not going to happen, so I think we ought to toss the ball back in the Nigerian court and ask them to explain these curious and unusual charges.''

The U.S. Embassy in Lagos reiterated its condemnation of terrorist bombings and expressed willingness to cooperate with Nigerian authorities.

Relations between the United States and Nigeria have been strained badly in recent years. Washington imposed sanctions in 1995 after the execution of nine political dissidents.