HENDERSON, N.C. (AP) — A Greyhound bus slammed into a tractor-trailer Wednesday and plunged down an embankment, injuring about 50 people, officials said.

At least two people were critically injured and airlifted to UNC Hospitals in Chapel Hill, said hospital spokeswoman Stephanie Crayton.

The bus was traveling from Richmond, Va., to Raleigh on U.S. 1 when a tractor-trailer ahead of it made a turn and the bus failed to slow down, said Sgt. Steve Green, a spokesman for the North Carolina Highway Patrol.