One suspect has been arrested and another is being sought after three people were killed in a shooting at a crowded food festival in the US city of Seattle, police said.

Assistant chief Tyrone Davis said detectives do not have any description of the outstanding suspect.

Investigators in Washington state believe the two suspects were shooting at each other and there is no ongoing threat to the public.

The gunfire erupted at around 6pm local time (2am BST) in the waning hours of the Bite of Seattle, an annual festival that draws hundreds of food and retail vendors and performers.

Three people died and four others who were injured are in stable condition in hospital, officials said.