WASHINGTON

The number of people injured after a Delta passenger jet crashed while landing at Canada's Toronto Pearson International Airport has risen to 21, as authorities probe the cause of the accident Tuesday.

Of the 21 who were injured in Monday's crash, 19 have been released from hospitals, the airliner said in a statement.

“Our most pressing priority remains taking care of all customers and Endeavor crew members who were involved,” Delta CEO Ed Bastian said. He was referring to Endeavor Air, Delta's subsidiary that ran Monday's flight.

“We’ll do everything we can to support them and their families in the days ahead, and I know the hearts, thoughts and prayers of the entire Delta community are with them. We are grateful for all the first responders and medical teams who have been caring for them.”

It is not yet clear why Flight DL4819 from Minneapolis-St. Paul crashed, but a video posted to social media shows it skidding along the runway as flames erupt as the fuselage flips over before it comes to a screeching halt.

Canada's Transportation Safety Board is leading the ongoing investigation.

Authorities are expected to brief reporters Tuesday morning with the latest information about the crash.