KABUL, Afghanistan — President Hamid Karzai, responding to recent allegations that insiders close to him are plundering the nation’s mineral wealth, said Sunday that the United States and British governments had given their imprimatur as to how a lucrative oil contract was awarded.

Mr. Karzai’s office put out a statement saying that he met Saturday with the American and British ambassadors to Kabul to clarify recent reports of bias and that both men had agreed that the concession awarded to a Chinese company and a local Afghan company was done so transparently and fairly.

“The U.S. and U.K. ambassadors confirmed the transparency and fairness exercised in the Amu Darya oil tender,” according to the statement, which was accompanied by a photograph of the United States ambassador, Ryan C. Crocker, and other officials meeting with Mr. Karzai and the Afghan mines minister, Wahidullah Shahrani. The statement said experts from the American and British governments had properly audited the process by which the contract was awarded and it was done according to international best practices. Although it is unusual for a foreign government to claim independently the support of outside nations against internal criticism, the United States on Sunday supported Mr. Karzai’s assertion.

“We have no problems with the characterizations in the news release and we have nothing more to add,” said Gavin Sundwall, a spokesman for the American Embassy in Kabul. The British Embassy in Kabul offered no comment.