SEATTLE -- A truck hauling a crane was burning on northbound Interstate 5 at Mercer Street.

The truck fire was on the shoulder of the road and started shortly after 2 p.m. Friday.

All lanes of north I-5 at Mercer Street were blocked while crews put out the fire. Chopper 7 over the scene showed traffic backed up for miles.

Brush above the freeway also caught on fire, said WSDOT.

There is no word on the cause of that truck fire.