By Staff, Agencies

US officials warned Friday of potential "mass" fatalities as more than 20,000 firefighters from across the country battled sprawling deadly wildfires up and down the West Coast that have scorched a landscape the size of New Jersey.

A prediction of cooler weather offered some hope of respite in the coming days, but the true scale of the destruction from dozens of massive blazes in California, Oregon and Washington states remained hard to gauge.

"We're preparing for a mass fatality incident based on what we know and the number of structures that have been lost," warned Andrew Phelps, director of the office of emergency management in Oregon on Friday.

At least 25 fatalities were confirmed by authorities, according to Reuters.

In the state of Oregon, which has become the blazes' epicenter, thousands of homes were destroyed in days.

Oregon Governor Kate Brown warned Friday that the death toll could grow significantly higher as dozens had been reported missing in three counties.

“This is a climate damn emergency. This is real and it’s happening. This is the perfect storm,” California Governor Gavin Newsom told reporters as quoted by Reuters.

In California alone, more than 3,900 homes and other structures have been incinerated in three weeks.