A charter bus bound for a casino in Oklahoma crashed off the President George Bush Turnpike near Dallas, Texas, Thursday.

Two passengers died as a result of the crash, after the bus hit a concrete barrier and flipped, reports the Texas Department of Public Safety.

Spokesperson Lony Haschel told USA Today the bus impaled a rubber portion of the barrier on the turnpike, bounced across the lanes to a grassy area on the shoulder, then hit another concrete barrier while flipping over.

Sixteen passengers are in critical condition, and as many as 20 have been hospitalized, reports NBC5.

The majority of the passengers were elderly people who were on their way to the Choctaw Casino Resort in Durant, Oklahoma for an all-day gambling event put on by the Cardinal Coach Lines, based in Mansfield, just south of the Dallas Area.

The trip to the gambling spot was organized by a woman the group called Casino Sue. It is being reported that the  passengers boarded the charter bus in Hurst, Texas.

According to a passerby and rescue officials, a large portion of the passengers were stuck underneath the bus, screaming for help amidst pools of blood and bodies.

Passenger Dan Risik told NBC5 that after hearing a deafening crash, "the bus started to veer back and forth and ended up flipping over on its side. People were screaming on top of each other."

Risik was among one of the lucky ones, he only suffered a bloody nose.

The bus was northbound on State Highway 161 when it collided. No reports have been made about the actual cause for the crash; was it the driver's fault, or a mechanical issue?

The turnpike has since been shut down, with no word as to when it will open up for traffic once more.