(CNN) -- United Nations officials apologized to Belarus this week for an incorrect report accusing it of shipping attack helicopters to the disputed president of the Ivory Coast.
The U.N. peacekeeping chief said his office received the erroneous report from a Security Council group of experts that is tasked with making sure an arms embargo imposed against the west African nation is implemented.
"This (is a) troubling event and a mistaken report," Alain Le Roy, head of U.N. peacekeeping operations, said in a statement.
A spokesman for U.N. Secretary-General Ban Ki-moon made the accusations against Belarus on Monday.
He said Belarus was defying the arms embargo by delivering three helicopters and other related material to Yamoussoukro, the capital of the Ivory Coast. A team sent to investigate the possible breach of sanctions was attacked by local security forces, the U.N. said.
The Belarusian Foreign Ministry denied it had delivered arms to the nation, saying the report is part of a campaign of "lies and slander."
Laurent Gbagbo, the incumbent leader in the Ivory Coast, is clinging to the presidency despite an international call for him to step down. An electoral commission declared challenger Alassane Ouattara the winner of a November election.
The United Nations considers Ouattara the winner as well.
Clashes between their supporters have left about 365 people dead since December, the United Nations said.
The U.N. imposed an arms embargo seven years ago after a civil war in 2002 split the country into a rebel-held north and a government-controlled south