An Air Canada flight has made an emergency landing at Madrid airport after the jet suffered what the airline described as an "engine issue".
The landing of flight AC837 was reportedly safe, according to an air traffic control source.
Fire engines were seen driving to the aircraft, but footage seems to show that no fire had happened.
A Spanish pilots union said the flight was returning to Madrid because part of the landing gear had fallen into the engine.
Flight AC837 spent several hours circling to the south east of Madrid, in an effort to burn fuel before landing.
The airport operator said the pilot called air traffic control 30 minutes after takeoff to request an emergency landing.
A drone sighting earlier on had caused disruption as the airport, with 26 flights being diverted from Madrid, but officials are unable to confirm whether the two incidents are related or not.
A spokesperson for Air Canada told Sky News: "Air Canada flight AC837, Madrid to Toronto, experienced an engine issue shortly after take-off. A tire also reportedly ruptured on take-off, one of 10 on this model of aircraft.
"The aircraft opted to return to Madrid and is currently circling to use up fuel and lighten the aircraft for landing.
"The aircraft, a Boeing 767-300, is designed to operate on one engine and our pilots are fully trained for this eventuality.
"Nonetheless, an emergency was declared in order to obtain landing priority.
"There are 128 passengers on board. We have no further details on the cause at present."
The aircraft has been part of the Air Canada fleet since 2005 and it took its first flight in 1989.
Reporting by IRN
