Investigators say one of the dozens of fires devastating the US might have been lit deliberately.
The Alameda fire started late on Tuesday morning in Ashland, a city of around 21,000 residents in southern Oregon, near the border with California.
Two bodies have been found and around 600 homes have been destroyed, although more victims are expected to be found as search teams continue to sort through wreckage.
Driving through flaming roads in Oregon
Ashland’s police chief Tighe O’Meara said detectives were treating the fire as suspicious but he gave no further details.
He said: “We have good reason to believe that there was a human element to it.
“We’re going to pursue it as a criminal investigation until we have reason to believe that it was otherwise.”
Rich Tyler, a spokesman for the state fire marshal’s office, said: “Every fire is investigated for the possibility of arson so that we can either determine it is or rule it out.”
Some 600 buildings have been destroyed so far in the Alameda fire
There are few residents still in the area, as it is off limits to evacuees.
Mr O’Meara said: “We tried to get people out as fast as we could.
“Chances are there are going to be bodies in some of those homes. The likelihood of much larger (fatality) numbers is significant.”
Ashland escaped with relatively little damage but the flames were driven by high winds into neighbouring communities along Bear Creek, the towns of Talent and Phoenix and towards Medford, a city of 82,000 people.
Photos showed burnt-out vehicles and gutted buildings along state highway Route 99 between Ashland and Medford.
As of 10 September, there were 37 active fires in Oregon, with more than 672,000 acres burning across the state.
There are also dozens of fires burning in northern California and Washington state.
At least nine people have been confirmed dead, including a 12-year-old boy.