The White House says there is no indication that terrorism was involved in Saturday's apparent breakup of the space shuttle Columbia, minutes before it was due to land in Florida.
President Bush was briefed on the disaster Saturday morning by chief of staff Andrew Card, and decided to return to the White House from the presidential retreat at Camp David, where he was scheduled to spend the weekend. Just before the president's arrival, the White House flag was lowed to half staff.
Spokesman Scott McClellan says Mr. Bush spoke with NASA administrator Sean O'Keefe about 10:30 a.m. local time, and will continue to be briefed throughout the day.
Mr. McClellan says White House staff also notified Vice President Dick Cheney, Defense Secretary Donald Rumsfeld and National Security Advisor Condoleezza Rice.
A Bush administration official says, there is currently no indication that terrorism was involved, but the incident is being investigated fully. Flight controllers lost contact with the space shuttle at an altitude of about 61,000 meters, well beyond the range of surface-to-air missiles.
Homeland Security Secretary Tom Ridge has been in touch with local officials in the states of Texas, Louisiana, New Mexico and Arizona about procedures for collecting debris from the fallen shuttle. The U.S. space agency is warning civilians to stay away from any debris as it may contain hazardous materials.
U.S. officials have also spoken with the Israeli government, as one of the astronauts on the shuttle was Israeli air force colonel Ilan Ramon.
Israeli Prime Minister Ariel Sharon's office released a statement saying the government and people of Israel "are praying together with the entire world for the safety of the astronauts."
Mr. Ramon was the first Israeli to fly in space. His presence on the flight brought about increased security both at the launch and its expected landing.