A man has been arrested on suspicion of arson over the largest of the wildfires that have forced more than 60,000 people to evacuate from the city of Spokane in Washington state.
Three major fires have been burning around the north-western state's second-most-populous city since the weekend, with firefighters still working to contain the flames.
Aaron Farinacci, 37, was allegedly seen kneeling near grass at the site of the fire and later found to have matches and a lighter, the Spokane County Sheriff said.
More than 700 buildings in the area have been destroyed, with another 400 yet to be assessed, and thousands of acres of land have been burned.
Washington Governor Bob Ferguson said it was a "nightmare situation", adding: "This is likely the worst natural disaster in Spokane history."
The city's mayor Lisa Brown said there was still "the potential for lives to be lost" and that it was too early to say when people might be able to return home.
No deaths or injuries have been confirmed.
Authorities are trying to make contact with 14 people they have been unable to reach by mobile phone but are not yet considered missing.
Sheriff John Nowels said it was likely many of them did get evacuated but had lost signal or had depleted phone batteries.
The three fires in the city - Old Trails, Fairview and Autumn Lane - are among a total of 16 wildfires in Washington state, according to the state's department of natural resources.
Firefighters have made progress against two of them but while lighter winds and cooler temperatures have been forecast on Tuesday, temperatures are feared to be rising again later this week.
Farinacci, who was arrested over the Old Trails fire, is being held on a charge of arson in the first degree and held on a $1m (£744,150) bond.
Nowels said the Spokane resident had a previous manslaughter conviction.
