LONDON (AP) — Nigeria's president says he won't demand an apology after British Prime Minister David Cameron called his country one of the world's most corrupt nations.

Cameron is hosting an international anti-corruption summit in London on Thursday. At a Buckingham Palace reception on Tuesday, a television microphone caught Cameron saying the "leaders of some fantastically corrupt countries" were coming.

Cameron referred to "Nigeria and Afghanistan — possibly two of the most corrupt countries in the world."

Nigerian President Muhammadu Buhari, who is due to attend, said Wednesday that "I am not going to demand any apology from anybody."

Speaking at an anti-corruption meeting ahead of the summit, Buhari says he wanted the return of plundered Nigerian assets held in British banks.

"What would I do with an apology? I need something tangible," Buhari said.

He described corruption as "a hydra-headed monster and a canker that undermines the fabric of all societies. It does not differentiate between developed and developing countries."

Asked about the gaffe in the House of Commons on Wednesday, Cameron said the leaders of Nigeria and Afghanistan were "battling hard against very corrupt systems" and had made "remarkable steps forward."