The all-clear came within minutes when two fighter jets intercepted the small twin-engine propeller-driven plane eight miles northeast of the Capitol. The alert ended before evacuations were complete at the White House.

The White House briefly went to red alert _ its highest level, presidential spokesman Scott McClellan said.

The private turboprop entered restricted airspace northeast of Reagan National Airport, according to federal aviation officials. Jets scrambled from Andrews Air Force Base, Md., intercepted the plane and, as of 6:45 p.m. EDT, escorted the plane to Winchester, Va., where it landed without incident.

An aircraft could be heard overhead at the Capitol, in an area customarily closed to aircraft.

Sen. Tom Harkin, D-Iowa, said Capitol Police notified senators' offices: "This is an emergency message ... Capitol Police are tracking unidentified aircraft."

At the White House, Bush had left the Oval Office for the day and was in the residence when the alert sounded. "The president was temporarily relocated," McClellan said. Some senior staff also were seen hurrying from the West Wing to the residence area where a bomb shelter is located.

"We started to relocate some staff," McClellan said. "Officers were prepared to activate the (White House-wide) alert system but we received notification from the jets that were scrambled that the plane had turned away from the White House."

Capitol Police Chief Terrance W. Gainer said the Capitol was ordered evacuated when the plane was about 5 minutes away. It was traveling southwest, then turned south toward the Capitol, but headed away a minute and a half later, Gainer said.

The plane originated in Delaware and was headed to Ohio, said Gary Bracken, a spokesman for the Bureau of U.S. Customs and Border Protection. Bracken said the pilot wrote a flight plan but did not file it with federal officials.

The House and Senate were both voting when the alarm sounded. In a virtual replay of a scare earlier this summer, members of Congress, staff, visitors and others were told to leave the building quickly.

Agents ran out of the gate from the White House compound onto Pennsylvania Avenue and began clearing pedestrians from the street. At first, officers did not seem hurried, and pedestrians were walking casually. "It's in your best interest to hurry along," an agent said.

The scare lasted about 10 minutes at the White House before officers gave the all-clear and Pennsylvania Avenue was reopened.

The offending plane was a King Air 350, said Michael D. Kucharek, a spokesman for North American Aerospace Defense Command in Colorado.

After it was detected, two Air Force F-16 Fighting Falcons scrambled from Andrews and it, Kucharek said.

The fighters "got the pilot's attention pretty quick," Kucharek said. Because of that, the fighters did not need to drop flares, and the laser warning system was not employed.

The pilot of the plane was Scott Murwin of Athens, Ga., a longtime pilot for Standridge Color Corp., a plastics products company based in Social Circle, Ga., his wife confirmed.

"He was at the wrong altitude," Debbie Murwin said in a brief telephone interview from her home.

Standridge Color Corp. president Bob Standridge said that he had not talked to Murwin but that Murwin had dropped off some Standridge employees to attend a seminar in Wilmington, Del., and was heading for Ohio when the flight was intercepted.

"I assume it's a simple mistake, the gentleman's been a pilot for several years," said Standridge, who said federal authorities planned to talk with company officials Thursday morning.