WASHINGTON, May 11: The official district of the US capital was in total panic for one hour on Wednesday afternoon as a small plane intruded into the restricted airspace over Washington. The frantic evacuation at the White House and the Capitol building began around 11.45 am and soon spread to other offices as well. There was total mayhem as people rushed out of their offices and drivers jammed the roads leading out of the city in an effort to move out to safety.

“You’ve got one minute,” a police officer yelled to people at the Capitol Hill. Staffers were directed to the basement where special arrangements have been made for sheltering people after the Sept 11 terrorist attacks.

Although officials soon gave the “all clear” signal, people were still seen leaving the city an hour after the alert was called off because they did not hear the signal or did not want to risk going back.

At the White House, which was the main target of the 9/11 terrorists who hit the Pentagon instead, the scene was even more alarming.

President Bush was exercising on his bicycle and was not at the White House at the time. Vice President Cheney was at the White House and was evacuated; a motorcade was seen speeding away from the White House shortly after the evacuation notice was given.

As military jets scrambled over the area, officers also rushed through the Supreme Court building and told staff to get into the basement. At the Treasury Department, people were moved across the street.

Initial reports said a Cessna aircraft had entered the restricted airspace, then turned away but returned. It was not clear whether the aircraft inadvertently entered the restricted area, but such incidents have happened before.

Later, officials told reporters that there was no indication a terrorist attack was under way. The plane was escorted by a fighter aircraft and forced to land at an airport in Leesburg, Virginia, about 35 miles from Washington.

House Speaker Dennis Hastert was on the House floor talking to members when the evacuation siren went off. He left quickly with his security detail. Two large black armoured SUVs often used by House and Senate leaders sped away from the Capitol as a military jet flow overhead.

“People were surprised. I was surprised,” said Rep. Bob Ney, a Republican from Ohio, who was on the House floor when the evacuation began. “There was so much commotion in the gallery. People were yelling in the gallery. We thought something had happened in the gallery, and then the alarm came to evacuate.”