Northwest Airlines cancelled a flight set to leave from Las Vegas to Detroit after the captain cursed on a cell phone in a bathroom, then swore at one of the 180 passengers on the plane, officials said on Saturday. "He used what was described to me as rude language," Ian Gregor, a spokesman for the Federal Aviation Administration, said about Friday's incident on Northwest Flight 1190. "At some point during the boarding process, he left the cockpit, went into the front lavatory, locked the door and continued his conversation. "Passengers who were boarding the aircraft could hear his end of the conversation through the lavatory door." When the captain emerged from the bathroom, a passenger confronted him about his behaviour, reportedly prompting more cursing by the pilot of the B757 aircraft. Local police questioned the captain, whose name was not released, and determined there was no cause to conduct a sobriety test, Gregor said. But Northwest cancelled the flight and flew the pilot back to his base in Detroit. The airline said it expected to get the last of the delayed passengers to their destinations by Sunday. "Northwest is conducting a review of the matter and has apologized to its customers for the inconvenience," the company said in a statement.