Updated at 4:57 p.m. ET
CHALDOVAR, KyrgyzstanThe search for three crew members of an American military refueling plane has been suspended for the night.
The plane crashed today in the rugged mountains of the Central Asian nation of Kyrgyzstan; a country where the U.S. operates an air base to help its war effort in Afghanistan. There's no word on the fate of the crew.
Pieces of the plane were left scattered across a grassy field bordered by mountains.
A U.S. defense official in Washington says the plane was on a refueling mission for war operations in Afghanistan at the time of the crash.
According to an official in Kyrgyzstan, the front section of the plane hasn't yet been found. The rest of the aircraft was badly burned in the crash.
He says the search for the crew will resume tomorrow morning. The crash site will remain under guard.
The plane crashed in the afternoon near Chaldovar, a village about 100 miles (160 kilometers) west of the U.S. Transit Center at Manas base, which is outside the Kyrgyz capital of Bishkek.
The plane was on a refueling mission for Afghanistan war operations at the time of the crash, a U.S. defense official in Washington said, speaking anonymously because he was not authorized to discuss the details of an ongoing investigation.
Emergency officials said the front section of the plane has not yet been found, the Russian state news agency ITAR-Tass reported from Bishkek.
A resident of the agricultural and sheep-grazing area said the plane exploded in flight.
"I was working with my father in the field, and I heard an explosion. When I looked up at the sky I saw the fire. When it was falling, the plane split into three pieces," Sherikbek Turusbekov told an AP reporter at the site.
The U.S. base, which is adjacent to Manas International Airport outside Bishkek, was established in late 2001 to support the international military campaign in Afghanistan. It functions as an interim point for troops going into or out of Afghanistan and as a home for the tanker planes that refuel warplanes in flight.
The base has been the subject of a contentious dispute between the United States and its host nation.
In 2009, the U.S. reached an agreement with the Kyrgyz government to use it in return for $60 million a year. But the lease runs out in June 2014, and the U.S. wants to keep it longer to aid in the withdrawal of troops from Afghanistan. Kyrgyzstan is reluctant to extend the lease.
On Monday, a Boeing 747 cargo plane crashed just after takeoff from the U.S. military base in Bagram, Afghanistan, killing all seven people aboard.