The Vietnam Consulate General in San Francisco has reported a ‘duck boat’ tour vehicle and a charter bus carrying students, 29 of which are Vietnamese, to a college orientation event collided on a busy Seattle bridge.

The accident occurred at 11.13am on September 24 (local time), killing four students and injuring dozens of others.

The Consulate General will update the names of the Vietnamese students after more information form the San Francisco Bureau of Diplomatic Security becomes available.

The crash happened on the Aurora Bridge, which carries one of the city's main north-south highways over a lake. At least two people were in critical condition among the 51 people authorities said were transported to hospitals.

There was no immediate word about the cause of the crash, which involved a military-style tour bus that can also be operated on water. Initial reports described the accident as a head-on collision.

"We didn't see anything. Just the sound. The smell of gas," said Rujia Xie, a 16-year-old from China, who was on the bus carrying about 45 North Seattle College students and staff.

She said glass fell on their faces, and some people jumped from the bus.

Families whose children are participating in the student exchange program with North Seattle College can contact hotline 415-425-0228 to find out more information.

VOV