The US Capitol and White House were evacuated on Wednesday after a small plane entered restricted airspace.

Military jets scrambled to intercept the aircraft and fired warning flares.

Two men in the aircraft later were taken into custody at a Maryland airport where the plane landed after a military escort, said Capitol Police Chief Terence Gainer.

"This appears to be errant pilots," he said, adding that officials were concerned because the plane appeared to be "on a straight-in shot toward the centre of the Washington area".

White House spokesman Scott McClellan said the plane came within three miles of the White House. President Bush was not there at the time.

Security officials in several other government buildings, including the Treasury Department and the US Supreme Court, ordered people to safer locations.

Bush was biking at Patuxent Wildlife Research Center in suburban Maryland, McClellan said.

Vice President Dick Cheney, in the White House, was moved to a secure location elsewhere, said a senior administration official.

Congressional leaders were hustled from the Capitol by armed officers. The threat level at the White House was raised to red - the highest - for eight minutes.

The incident began at 15:28 GMT when Federal Aviation Administration radar picked up the aircraft, a small two-seater Cessna 150 with high wings, officials said.

The aircraft breached the security zone over Washington, law enforcement officials said, prompting alerts across the city.

PHOTO CAPTION

General view of the White House in Washington. (White House archive)