A Metrobus crashed into a passenger vehicle early Sunday afternoon, prompting multiple subsequent collisions and sending four people to the hospital, authorities said.

The victims included one person who was in serious condition with potentially life-threatening injuries, said Pete Piringer, spokesman for Montgomery County Fire and Rescue Service.

The collision occurred about 12:20 p.m. when the bus, traveling south on Rockville Pike, “lost control and swerved onto Congressional Lane,” causing a “chain reaction” of collisions, Montgomery County police said in a news release.

The bus, which had no passengers aboard, struck a Honda Passport and landed in part on top of the Passport, said Shiera Goff, director of public information for Montgomery County police. That initial collision then led to multiple subsequent collisions, she said.

In all, four vehicles, plus the bus, were involved in the incident, Goff said.

Montgomery County’s collision reconstruction team was investigating. Nobody was immediately charged.

The collision temporarily shut down southbound traffic on Rockville Pike and on Congressional Lane, authorities said.