London - Nigerian President Muhammadu Buhari said on Wednesday that he did not want an apology from Prime Minister David Cameron for calling his country "fantastically corrupt", but said Britain could return assets stolen by officials who fled to London."I am not going to demand any apology from anybody. What I am demanding is the return of the assets," Buhari told an anti-corruption event hosted by the Commonwealth Secretariat in London.He noted the case of Diepreye Alamieyeseigha, a former governor of oil-rich Bayelsa state who was detained in London on charges of money-laundering in 2005, but skipped bail by disguising himself as a woman.Alamieyeseigha, who died in Nigeria in October, left behind "his bank account and fixed assets, which Britain is prepared to hand over to us. This is what I'm asking for," Buhari said."What would I do with an apology? I need something tangible," he said.Cameron is hosting a major anti-corruption summit in London on Thursday, which Buhari is attending alongside Afghan President Ashraf Ghani.But in a diplomatic gaffe, Cameron was caught on camera on Tuesday saying that the leaders of some "fantastically corrupt" countries were attending."Nigeria and Afghanistan, possibly the two most corrupt countries in the world," he was filmed telling Queen Elizabeth II at an event at Buckingham Palace.Buhari has embarked on a widespread anti-corruption campaign since taking office last year, and in his speech to Wednesday's Commonwealth event thanked Britain for helping recover stolen assets taken abroad.‘Time consuming’"Even before this government came in, the UK took the initiative of arresting some former governors of some of the states in Nigeria," Buhari said. But in general, he said, "our experience has been that repatriation of corrupt proceeds is very tedious, time consuming, costly".Other Nigerian politicians were less forgiving of Cameron's comments."I am taken aback. I am not happy about it," said Senator Chukwuka Utazi, chairman of the senate committee on anti-corruption and financial crimes, at the Commonwealth event."If there's no market for stolen goods, then there would not be a thief. As long as the criminals steal, and Britain is ready to welcome them over here... it smacks of irresponsibility," he said.Senator Dino Melaye said he wanted an apology for Cameron's "reckless" and "demeaning" remarks about his country."I would expect David Cameron should be busy answering questions on the Panama saga than insulting the integrity of my nation," he said."Nigeria, like many other countries across the globe, is corrupt, but corruption is a two-way traffic. The UK cannot continue to encourage and warehouse the proceeds of corruption and then accuse nations of being corrupt."Melaye, a public supporter of Senate president Bukola Saraki who is currently on trial for fraud, said the money involved "amounts to billions of pounds stolen from Nigeria, deposited in properties and cash in the UK".