Britain's Office of Fair Trading (OFT) and the U.S. Department of Justice are investigating alleged cartel activity involving British Airways Plc (BA) and other airlines, BA said on Thursday.

The investigation relates to pricing of passenger air transportation including fuel surcharges, BA said in a statement, adding its policy is to conduct its business in full compliance with all applicable competition laws.

BA also said its commercial director, Martin George, and head of communications, Iain Burns, had been given leave of absence during the investigation.

BA would make no other comment.

An OFT spokeswoman confirmed an investigation was under way but gave no other detail.

BA shares fell 3.2 percent to 356 pence in early trading which saw the blue-chip FTSE 100 index rise 1.3 percent.