The U.S. space shuttle Columbia has broken apart over Texas -- minutes before it was due to land in Florida and the seven crew members are feared dead.
A senior U.S. official says simply, the shuttle is gone.
The U.S. space agency NASA has lowered flags to half-staff at the Kennedy Space Center in Florida and is to hold a news conference shortly (1:00 pm EST). Debris from the shuttle is being found on the ground in central Texas and possibly other states.
NASA declared an emergency and mobilized search and rescue crews after communication was lost with Columbia earlier today (Saturday), as it prepared to land with six American crew members and the first Israeli astronaut, Ilan Ramon.
Television footage from north-central Texas showed multiple trails as the shuttle streaked across the sky, indicating that it had broken up. There is no word on what caused the break up.
NASA officials are advising residents of Texas not to handle any debris from the 22-year-old shuttle. Texas residents say they heard a loud noise about the time the shuttle disappeared, shaking local homes. They say they saw flaming debris falling to earth.
Security was tight at the Kennedy Space Center in Florida for the expected landing to prevent any possible terrorist attack. However, U.S. officials say there is no indication terrorism was involved, but the incident is being fully investigated.
Columbia was returning after a 16-day scientific mission. In more than four decades of U.S. human space flight, NASA has never lost an astronaut during the descent and landing of a spacecraft. In January 1986, space shuttle Challenger exploded shortly after lift-off.
The Columbia crew had completed more than 80 experiments that focused on weightlessness, advanced-technology development and the health and safety of astronauts. Columbia was NASA's oldest shuttle and first flew in 1981.
Information for this report is provided by AP and Reuters.