Thick black smoke rises from truck fire in downtown Denver

A burning truck put out a lot of black smoke in downtown Denver on Friday morning. Firefighters rushed to put out the fire in a parking lot at 6th and Broadway just before 9 a.m. 

The truck was engulfed in flames and crews said no one was inside the vehicle. No other vehicles were involved and none of the buildings nearby were damaged. 

What caused the fire is being investigated.