Investigation underway into why U.S. Delta plane flipped on roof

NEW YORK, Feb. 18 (Xinhua) -- Investigators have begun working to identify what caused a Delta Air Lines regional jet to flip on its roof while landing at Canada's Toronto Pearson International Airport, injuring 21 of the 80 people on the flight from Minnesota.

The passenger jet was carrying 76 passengers and four crew members and crashed as it was attempting to land around 2:15 p.m. local time, Delta said in a statement. The CRJ-900 regional jet had departed from Minneapolis-Saint Paul International Airport.

Twenty-one passengers were transported to area hospitals on Monday, according to Delta, and 19 had been released by Tuesday morning. Of those injured, two adults were taken to two different trauma centers by air ambulance and one child as transported to a children's hospital, according to local officials.

Immediately after the crash, the busiest airport in Canada shut down all of its runways. The airport resumed departures and arrivals by 5 p.m. but cancellations and delays have since piled up.