Firefighters battling the blaze threatening a top US nuclear weapons research lab are optimistic they are gaining control of the fire.
"It's been a great day," said Doug Tucker, fire chief of Los Alamos, New Mexico. "Everything is holding."
The firefighters have cleared brush and used flame-retardant foam to hamper the spread of the blaze.
The fire started on Sunday. Officials say nuclear waste at the laboratory is not threatened by the blaze.
The town of 12,000 people near the complex was evacuated Monday, and authorities have not said when they can expect to return.
Meanwhile, thousands of sophisticated experiments underway at the lab, where the world's first atomic bomb was developed in 1945, remain at a standstill.
The Las Conchas fire has now burned 145 sq miles (375.5 sq km), fuelled by dry timber and powered by strong winds. Smoke from the blaze can be seen as far away as Albuquerque 60 miles (100km) away.
The Los Alamos facility employs about 15,000 people, sprawls more than 36 sq miles (93 sq km) and includes about 2,000 buildings over about four dozen sites.
The wildfire has destroyed 30 structures south and west of Los Alamos.
On Thursday evening, fire officials told reporters that the more than 1,000 firefighters battling the blaze had begun to halt its advance.
"Tomorrow you're going to see a whole different landscape," Chief Tucker said.
They were using fire-retardant foam Chief Tucker described as similar to shaving cream, and using heavy kit and "controlled burns" to clear brush and timber fuel ahead of the fire's approach.
Air National Guard members from Colorado, California and North Carolina have also flown in to help local crews battle the fire near the lab, which remains closed to all but essential staff.
The Environmental Protection Agency has deployed air monitors and aircraft that can monitor radiation levels, amid fears the blaze could reach a cache of 30,000 drums, each containing 55 gallons (208 litres) of plutonium-contaminated waste.
The south-western US has been stricken by giant wildfires this year, with millions of acres scorched in New Mexico, Arizona and Texas.
To the west of New Mexico, the largest wildfire in the history of the state of Arizona has been burning for nearly a month.