IRVING, Texas (Kiii News) - Two people died and at least 41 were sent to the hospital when a charter bus overturned Thursday morning in Irving, Texas.

It happened on State Highway 161, about 15 miles outside of Dallas. Authorities said a Cardinal Coach Line bus was headed to a casino when it slid off the highway, rode up onto a concrete barrier and flipped onto its side.

Witnesses said they saw people pinned under the bus.

"The injured parties are being tended to as we speak," said Trooper Lonny Haschel of the Texas Department of Public Safety. "It's an active scene. We have several EMS folks coming in, in kind of an assembly line, and we are shipping people to various hospitals throughout the Metroplex."

"We have received nine patients," said Michael Malaise, Interim Senior Vice President of External Affairs. "We are currently assessing their condition. We are still accepting patients outside of this incident into our emergency room."

At least three people who were sent to the hospital were in critical condition. It is unclear what initially caused the bus driver to lose control.