Update: 2:03 p.m.

North Seattle College released a statement on the status of the students involved in the crash.

Uninjured students were transported back to North Seattle College and were met by school counselors for trauma support.

"We are working to learn the status of all students and employees involved in the accident and will provide an update as soon as possible."

It's known at this time that a least two of the four fatalities were riding in the charter bus carrying the North Seattle College staff and students.

Meanwhile the Aurora Bridge remains closed as Seattle Police Department investigates the cause of the accident.

Witnesses reported seeing a red liquid coming from the Duck vehicle before the crash.

Update: 12:43 p.m.

Seattle Fire Department announced that there are two more dead after an amphibious tour vehicle crashed into a charter bus that was transporting foreign students from North Seattle College.

"This a terrible tragedy. We need to give the police and the fire department the opportunity to do what they need to do to help people, to get this bridge cleared, to conduct and investigation. That's going to take many hours. It will go through this evening. We ask people to make plans...around this crisis and work with police and the fire department," said Mayor Ed Murray.

Seattle Fire Department stated that the Ballard and Fremont Bridges will not open for boats to relieve traffic congestion.

Original post:

A collision between an amphibious tour vehicle and a charter bus on Aurora Avenue Bridge earlier this morning has left two people dead, 12 critically injured and over 12 with non-threatening injuries.

Witnesses say that the Ride the Duck vehicle collided with the charter bus while going northbound over the narrow bridge. The bus was carrying Chinese students from North Seattle College.

Over 90 Seattle Firefighters were dispatched to the scene. A Seattle Fire Department Battalion Chief was able to get there quickly and set up a command center. Crews found the bus badly damaged and people trapped inside. Firefighters were able to extricate the victims and treat up to 50 people at an emergency trauma center they set up on the bridge.

Critically injured patients were rushed to Harborview Medical Center while victims with non-life threatening injuries were rushed to other area hospitals.

Mayor Ed Murray activated the Emergency Operations Center at 11:45 this morning to coordinate the response to the incident.

Sue Stangl from Seattle Fire Department reported that the bridge would be close into the night as Seattle Police investigate the crash.

SFD and SPD were unable to provide any additional information about the cause of the crash.