A US spy plane has crashed while returning to its base in the United Arab Emirates (UAE), killing the pilot, US officials have said.
The U-2 flies so high that the pilot is forced to wear a spacesuit
The U-2 plane had completed a mission in support of US forces in Afghanistan when the crash occurred on Tuesday.
The cause is unclear - but there is no indication that hostile fire was involved, Pentagon officials say.
Washington has an agreement with the UAE, allowing US forces to use some of the country's military facilities.
The U-2 is a high-altitude surveillance aircraft first developed in the Cold War and manned by a single pilot.
Pentagon officials - speaking on condition of anonymity - told US media that the plane had come down as it was trying to land in the UAE.
The military has not so far officially confirmed the location of the crash citing "host nation sensitivities".
The pilot's unit - the 380th Expeditionary Wing - is based at the Al-Dhafra air base, near Abu Dhabi.
The site of the crash has been secured and an investigation is underway.
The US military said the plane was returning from a mission in support of Enduring Freedom - codename for operations in Afghanistan.
The name of the pilot will not be released until next of kin are informed.
"The airmen of the 380th Expeditionary Wing mourn the loss of a true American hero in the service of his country," Col Darryl Burke, the wing's commander, said in a statement.
Cold War stalwart
The long, thin plane, with a wing-span of 100 feet (30.5m) is able to cruise at 90,000ft (27,430m) - more than 17 miles (27km) up - so high that the pilot has to wear a spacesuit.
U-2 pilot Gary Powers was famously shot down in 1960
The U-2 was an invaluable US surveillance tool during the Cold War, able to photograph Soviet military facilities and operating in great secrecy.
In 1960 a U-2 was shot down by a volley of Soviet surface-to-air missiles. The pilot, Gary Powers, ejected but was captured and held for two years on spying charges.
It was also a U-2 that took the photographs of Soviet missiles being put into Cuba in October 1962.
Defence experts say the original U-2 aircraft were highly unsafe and 80-90% of them eventually crashed or were shot down.
But later versions, the U-2R and U-2S, though 40% bigger, are much more reliable.