Four students killed, dozens injured in Seattle bus crash

A tour vehicle and a charter bus carrying foreign students have collided in Seattle, Washington state, leaving four people dead, US officials say.

TV footage showed an amphibious "Ride the Ducks" vehicle - a type used for tours in several US cities - smashed into the side of the bus on a bridge.

The four victims were foreign students from North Seattle College. Several people were critically injured.

Seattle Mayor Ed Murray described the crash as "a terrible tragedy".

It happened at about 11:00 local time on Thursday. Two smaller vehicles were also involved in the crash.

Most of the victims were on board the charter bus. Officials have not said which countries they were from.

Forty-five students and staff members from the school's international programmes were taking an orientation trip ahead of the school year starting on Monday.

Fifty-one people were taken to hospitals. Fire department officials said 12 had critical injuries.

"Today, the North Seattle College community learned devastating news that four of our students were tragically killed in a vehicle accident on the Aurora Bridge," the school said in a statement.

"Additionally, several students remain in critical condition, and other students and a North employee sustained serious injuries."

Government officials were working to contact next of kin.