WASHINGTON, Sept. 11 -- Standing in a devastated and still-burning Pentagon building, the nation's top military officer declared Tuesday that the military is ready to take action against the terrorists who planned and carried out a series of attacks, including one at the Pentagon that killed and injured dozens of military and civilian workers.
"I have no interest in discussing what comes next. But make no mistake about it: Your armed forces are ready," said the chairman of the Joint Chiefs of Staff, Gen. Henry Shelton, at a Pentagon news conference Tuesday.
Defense Secretary Donald Rumsfeld, flanked by Shelton, two senators and the secretary of the Army, declared the Pentagon open for business Wednesday.
"The Pentagon is functioning. It will be in business tomorrow," Rumsfeld said at a hastily called news conference at the Defense Department headquarters, its hallway still filled with acrid smoke.
"There is no question but that the attack on the United States of America was a vicious, well-coordinated massive attack against the United States," he said.
Senate Armed Services Committee Chairman Carl Levin, D-Mich., declared Congress unified behind President Bush.
"Our institution is strong and our unity is palpable," Levin said.
Rumsfeld confirmed that U.S. Air Force fighter aircraft have been flying "protective missions over parts of the United States today and they will continue to do that."
He would not, however, specify the number of dead and injured at the Pentagon, and neither would he say whether the Pentagon had any intelligence that warned of the attack.
Rumsfeld was in his office at the time of the attack and felt the shock wave rumble through the building. He went out to see the damage and saw people being hauled out of the wreckage.
"I saw (them) bring bodies out that had been injured, most of which were alive and moving, but injured," he said.
A hijacked American Airlines flight from Dulles International Airport crashed into the building's west side, between the first and second floors shortly after about 9:39 a.m. The impact collapsed five floors of a roughly 50-foot section, three hallways deep into the building.
The Pentagon is comprised of five concentric "rings," crisscrossed by hallways and numbered corridors. The impact occurred near the fourth corridor, and went through the outer "E" ring into the "C" ring, stopping short of the two inner rings, sending up a massive fireball. Pieces of the plane were scattered on a Web of commuter roads that ring the Pentagon.
The plane's nose drove into the wall of the building about the second story near the Pentagon's Heliport.
"The plane is buried down in the building," said Gov. James Gilmore, R-Va., who toured the devastation. Gilmore added: "There're obviously very major (casualties). Not just in New York but here as well."
A Pentagon spokesman said all employees should call the following numbers to sign into a "muster list," which will help determine the number of casualties and who is missing.
Members of the Army can call 1-800-984-8523, or 703-428-0002. Navy and Marine Corps personnel should call 1-877-663-6772, and members of the Air Force can call 1-800-253-9276.
The crash came less than an hour after two hijacked planes crashed into the twin towers of the World Trade Center in New York.
At 10:09 a.m. there was a secondary explosion, which rocked the entire parking lot area. Fire officials speculated it was caused by additional explosives in the aircraft.
Defense Protective Service chief John Jester told United Press International "Our first goal is to knock down the fire," adding that-- six hours after the crash -- small flames continued to lick at the roof of the building. "Then the search-and-rescue team can go in and see what we find inside."
No official count of casualties was available, but it seems certain that all of the 58 passengers and six crew-members on American Airlines flight 77 out of Dulles bound for Los Ageles were dead.
The Virginia Hospital Center Arlington said it had received 31 injured people by late afternoon Tuesday. Of those, six were treated and released and 15 were admitted for further treatment. The other 10 patients were being evaluated.
At the time of the attack, the Defense Department was fully staffed -- thousands of military and civilian personnel work there.
The explosion sent plumes of gray, black smoke 200 feet into the air and the entire west side of the Pentagon facing Arlington Cemetery was blackened by the blast. Cars on the nearby Route 27 toward Washington were thrown off the road by the force of the detonation.
A section of the building 50 feet wide and five stories high collapsed, allowing a view of the Pentagon's inner courtyard.
Tim Timmerman, a pilot who saw the impact from his apartment on the 16th floor of a building near the Pentagon, told CNN that a jet bearing American Airlines markings with its engines gunning came North, above Route 395, before accelerating and crashing into the helipad immediately adjacent to the West side of the building. Shortly afterwards, he said, the whole area was engulfed in flames.
The site of the crash and explosion was on the opposite side of the building from the offices of the Secretary of Defense and the Joint Chiefs of Staff.
Pentagon spokesman Rear Adm. Craig Quigley said all of the service chiefs and secretaries and the chairman and vice chairman of the Joint Chiefs of Staff are accounted for.
He said the U.S. military worldwide was at threat condition Delta -- the highest level of alert, called when there is an imminent threat or a terrorist attack.
Thousands of military and civilian employees were evacuated from the Pentagon on foot. The evacuation was orderly and many of the employees gathered around the scene.
At 10:23 a.m., police and fire officials evacuated an area about 3,000 yards further away from the building on all sides after a warning that a second aircraft might be on its way.
Pentagon officials said a casualty center was being established on nearby Fort Myer Army Base in Arlington, Va., and a press center was also expected to be set up there Tuesday evening.