UPDATE: The accident has been cleared and traffic is moving at normal freeway speeds.
A collision on Interstate 5 at Interstate 405 at Southcenter has created a 10-mile-long back-up on northbound I-5.
The accident was first reported at 6:55 a.m. Tuesday. The collision is blocking three lanes.
Fire Assistance and the Incident Response Team have arrived on the scene.
As of 7:30 a.m., traffic was stopped or moving slowly as far south as Federal Way.