The US space shuttle Columbia disintegrated in a fireball yesterday as it returned to Earth, killing all seven crew and scattering charred wreckage over a wide area.
NASA lost contact with Columbia as it hurtled over Texas, 16 minutes before it was due to land at Cape Canaveral in Florida. Several white trails were seen coming from shuttle as it split up.
President George W Bush paid tribute to the "courage and daring" of the dead astronauts, who included the first Israeli go into space.
"These men and women assumed great risk in this service to all humanity," Mr Bush said in a emotional nationwide address.
The Stars and Stripes flew at half-mast at the White House as grief spread across the United States. The disaster was also a national tragedy for Israel where the country's first astronaut, Colonel Ilan Ramon, was a national hero. Many world leaders called Mr Bush to express condolences.
NASA indefinitely suspended all space shuttle flights while an investigation goes ahead.
The loss of Columbia, the oldest of the shuttles, brought back sharp memories of the explosion of the Challenger as it took off from Cape Canaveral on January 28, 1986, also killing all seven people on board.
Columbia first went into oribit in 1981. The other remaining shuttles in the US fleet are Discovery, launched in 1983, Atlantis (1985) and Endeavour (1991), which replaced Challenger.
Columbia was on its 28th mission having just returned from a major refit. All of the shuttles were grounded for four months last year after cracks were found in part of their propulsion systems.
The Columbia crew and ground controllers noted problems with temperature sensors before the shuttle broke up but were not immediately concerned.
The last message from ground control to Columbia commander Rick Husband said: "To Columbia, here is Houston; we see your tire pressure messages and we did not copy your last" message.
After a moment, Husband replied: "Roger but ..."
After a brief crackling noise, the radio went silent.