Authorities were investigating an early morning explosion among a group of food carts in downtown Portland on Sunday.
The blast reported at about 3:40 a.m. shattered a large number of windows in the surrounding block, the Portland Police Bureau said.
Officers searched the area but found no one with any injuries.
There was no immediate word on a potential cause for the explosion.
Area streets were closed as a bomb squad swept the area for potential explosive devices.
