WASHINGTON, May 13: A student pilot and his instructor were released without charges on Wednesday after causing an emergency evacuation of thousands of people from the White House and the Capitol building in a terrorism scare earlier in the day. The two men’s small Cessna strayed into restricted airspace over Washington, coming within five kilometres of the key buildings.

The two men on board, student pilot Troy D. Martin, 36, and instructor pilot Hayden Sheaffer, were forced to land at an airport north of Washington and were arrested and questioned.

“This appears to be errant pilots,” Capitol Police Chief Terence Gainer said after the incident. Authorities said the Cessna’s radio appeared to have malfunctioned, so that the men couldn’t hear the repeated warnings sent to them.

The plane had wandered off course while heading to an air show in North Carolina. The plane is registered with the Vintage Aero Club, a group of 10 people who fly out of the Smoketown airport in Pennsylvania’s Lancaster County. President Bush was not at the White House when the plane entered the restricted airspace.

Vice-President Dick Cheney, Laura Bush and Nancy Reagan, who was in the town for some special event, were at the White House and taken to secure locations. The Treasury Department, the Supreme Court and other nearby offices were also evacuated.

“We have to remember we are a nation at war and there are people who will seek an attack on the United States,” said White House Press Secretary Scott McClellan.