TORONTO - A pilot's spilled coffee accidentally triggered a hijacking alert and caused a United Airlines flight from Chicago to Frankfurt, Germany, to make an unscheduled stop in Canada.

A Transport Canada report says United Flight 940 was diverted to Toronto late Monday and landed safely at Pearson International Airport. A emergency was declared and Canada's defense department was notified, but that with the help of United dispatch staff the flight crew confirmed it to be a communication issue and not a hijacking.

The report says the US Federal Aviation Administration reported that United's corporate office had indicated that the pilot "had inadvertently squawked a 7500 code after spilling coffee on the aircraft's radio equipment, which interfered with the communications equipment."