UPDATE 4:21 p.m. EDT: A North Carolina church says senior citizen members of its congregation were on the bus that crashed on I-40. They were on a trip to the Fall Jubilee in Gatlinburg, Tenn., according to WBIR.

UPDATE 3:39 p.m. EDT: The cause of the I-40 accident remains unknown. The Tennessee Highway Patrol told WBIR's Steve Butera that the bus was traveling eastbound on I-40 "and for an unknown reason, traveled across the median and struck a tractor trailer and passenger car."

Meanwhile, WBIR is reporting that 14 people were believed to be injured in the accident. Eleven people have arrived at the University of Tennessee Medical Center; four of the 11 were airlifted to the hospital.

UPDATE 3:39 P.M. EDT: The tractor-trailer involved in the three-vehicle crash caught fire during the I-40 accident, according to a tweet from WBIR. The Knoxville television station cited authorities.

UPDATE 3:17 P.M. EDT: The Tennessee Highway patrol says a bus, tractor-trailer and a car were involved in the accident, according to WBIR.

Multiple people were killed in a bus crash Wednesday afternoon near I-40 in Tennessee.

The wreck, in Jefferson County, shut down traffic in both directions of I-40, the Knoxville News Sentinel reported. The crash occurred around 2 p.m. Wednesday.

Knoxville television station WBIR tweeted that the highway is expected to be cleared by 9 p.m. EDT. While WBIR reported “several fatalities” in the bus crash, it’s unclear exactly how many people were killed in the accident: