US struggles against inferno

An exhausted US army infantryman gets some rest

Authorities in the US are warning that firefighting efforts risk being overrun by the huge scale of brush fires raging across 11 western states.

They are calling for additional national guard forces to be drafted in to help some 20,000 firefighters and 2,000 troops who have spent weeks battling blazes which stretch from the Rocky Mountains to the Pacific.

Teams from Canada, Australia and Mexico have already joined the effort.

The fires are leaving a trail of destruction

President Bill Clinton will travel to national firefighting headquarters in the state of Idaho later on Tuesday, where he is expected to offer words of encouragement to the exhausted fire crews.

Mr Clinton is expected to release $150m in federal aid.

Officials say these are the worst fires seen in the US for half a century, and attempts to contain them are costing the federal government $15m a day.

Residents flee

Idaho and neighbouring Montana are among the states hardest hit this week, with more than 20 large fires currently burning in the Rockies.

Our fire season could be another two months, maybe a little longer

Forest Service Chief Michael Dombeck

Police are urging hundreds of people in south-west Montana to heed evacuation orders as the fires threaten residential areas.

A Montana County Sheriff, Perry Johnson, warned people to move livestock and prepare to get out.

"If you choose wrongly... you may stay there forever," he said.

Overwhelmed

There were 65 major fires active on Monday that had burnt about 826,800 acres, according to the National Fire Information Centre in Boise, Idaho.

Fears are also growing that the fires could soon threaten ancient Pueblo Indian cliff dwellings, monuments and archaeological sites.

Helicopters are pounding the flames with water

The BBC's correspondent in Idaho, David Willis, says this is considered to be a crisis of epic proportions, with authorities conceding they are in danger of being overwhelmed.

Many fires in Idaho and Montana will probably burn until the snow season, said Forest Service Chief Michael Dombeck.

"Our fire season could be another two months, maybe a little longer," he said.

Shortage of manpower

Fires have smouldered in parts of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming.

US fire facts

Worst fire season in 50 years

More than 62,000 wildfires reported this year

1.52 million hectares burned

More than 20,000 firefighters now mobilised

Minimum 700 fire engines, 150 aircraft deployed

$15m a day to contain the fires

Water from lakes normally used for water sports is being collected by National Guard helicopters and dumped on the fires.

However, firefighters in Colorado battling a 5,000-acre blaze in the Mesa Verde National Park were given a boost on Monday when a rain storm swept over the area and stopped fires from spreading.

Fighting fire with fire

Firefighters also made headway against blazes in California and Utah over the weekend.

Military troops have joined forces with the firefighters

But the situation could worsen, with dry lightning storms expected this week in the eastern sierras of California, Utah and Washington.

In some states, firemen are trying to fight fire with fire by scorching areas in advance of the blaze, so there is nothing to feed the flames.

Propelled by high winds, the flames can travel a quarter-of-a-mile per minute. A single storm can cause as many as 300 new fires.