By David Schwartz and Timothy Pratt
PHOENIX/LAS VEGAS, July 5 (Reuters) - Even as crews in central Arizona made progress on Friday toward containing the deadliest U.S. wildfire in 80 years, another blaze burned out of control in the mountains northwest of Las Vegas, threatening 400 homes.
The 9,000-acre (3,600-hectare) Nevada blaze, like the Arizona fire that killed 19 firefighters last weekend, was sparked by lightning and fueled by dry conditions, strong winds and high temperatures, said Marty Adell, incident commander for the federal Bureau of Land Management.
Five days after it was ignited on Monday, the Nevada blaze was still completely uncontained, Adell said, although there were no reports of injuries or damaged buildings.
The Nevada fire forced the closure of two state highways on Friday. The night before, the Red Cross set up emergency shelters in Las Vegas and Pahrump, a community about 55 miles (88.5 km) to the northwest.
Smoke from the blaze was visible as far away as the Las Vegas strip.
In Arizona, where residents and emergency crews alike remain in shock over the loss of an entire elite firefighting team last week, the 8,400-acre (3,400-hectare) Yarnell Hill fire has been 90 percent contained, officials said.
The Arizona blaze also destroyed 114 buildings, many of them homes, since it was sparked by lightning on June 28.
U.S. Senator John McCain, who represents Arizona, said on Friday that the federal government should pump more money into clearing flammable brush in fire-prone areas, and expressed concern that the federal automatic spending cuts would affect wildland firefighting programs.
"We need to clear these forests and we need to make it so that the damage done by these fires is not as catastrophic as what we just saw, McCain said at a news conference in Prescott, the home base of the slain firefighters.
Weather forecasts called for cooler temperatures, which should help firefighters working to fully extinguish the blaze, about 70 miles (113 km) from Phoenix.
"We had a really good day yesterday and things are in place ... to have good success today," deputy incident commander Jerome McDonald told a news conference.
Officials said most of the hundreds of area residents were still unable to return home. McDonald said considerable work must be done before gas and electricity service can be restored.
Nineteen firefighters in a specially trained unit called the Granite Mountain Hotshots were killed while battling the blaze. It was the greatest loss of life from a wildfire since 1933, when at least 25 men died in 1933 battling the Griffith Park fire.
A memorial service to honor the 19 firefighters is scheduled for Tuesday at an arena in Prescott Valley, Arizona. U.S. Vice President Joe Biden is expected to attend. Officials plan to set up an overflow area to handle the crowd, expected to exceed the arena's seating capacity of nearly 5,000.
The firefighters' bodies will be taken in a procession from the medical examiner's office in Phoenix to Prescott on Sunday, the Prescott Fire Department said.
Federal investigators are probing the reasons for the deaths of the 19 firefighters who were overcome as they tried to battle the fast-moving blaze on rugged terrain. (Reporting by David Schwartz in Phoenix and Timothy Pratt in Las Vegas; Editing by Dan Whitcomb, Sharon Bernstein and Sandra Maler)