M.Mende said the AU delegation was welcomed, but the post-election process will remain unchanged.
Interim results announced last week showed a surprise victory for opposition leader Felix Tshisekedi. But Fayulu requested a recount, saying that she had won with more than 60 percent of the vote and that Tshisekedi was announced as the winner only after reaching an agreement with President Joseph Kabila who would leave.
The influential Congolese Catholic Church said official results were not consistent with the calculations themselves. Three diplomats who gave a brief explanation of Church findings said they pointed to a clear victory for Fayulu, Exxon Mobil's former state manager.
Both the Kabila camp and the Tshisekedi camp have denied such maneuvers. They also denied allegations of fraud.
But the AU statement put more pressure on Kinshasa to address what independent observers described as a serious weakness in the process including the wrong polling machines and polling stations where many could not vote.
AU approval for the results is very important for the legitimacy of the next president.
Congo, a vast and turbulent country of 80 million people scattered throughout central Africa, is the world's leading cobalt miner, which is used in electric car and cellular telephone batteries, and is the largest copper producer in Africa.