Police dogs continue to sniff cars as they enter the Capitol grounds, airport visitors still can't get to a gate without a ticket and the White House remains closed to public tours.

The Persian Gulf war is over, but Washington - and many parts of the nation - remain on heightened alert to possible terrorist attack."Even though the war is over, the threat of terrorism hasn't dissipated," Bob Buckhorn, a spokesman for the Federal Aviation Administration, said Thursday.

Buckhorn said airport security was placed at its highest level because of the war and "we have no immediate plans to reduce that level."

He said FAA officials review security needs periodically, "so at whatever point they feel that there may be reason to reduce the security they would do it."

Like other officials, Buckhorn declined to go into detail about what measures were taken, except for those changes that airport visitors can see for themselves.

These include more guards, some use of bomb detection dogs and allowing only ticketed passengers to reach boarding gates.

There is disagreement over whether it's a good idea to continue tight security measures that were imposed because of the crisis in the Persian Gulf. At the Arkansas State House in Little Rock, metal detectors that went up in January have been removed.

And a spokesman for the General Services Administration says the extra guards will go off duty soon in most federal buildings nationwide.

Frank G. McGuire, a former aviation writer who publishes Security Intelligence Report in Silver Spring, Md., said airports "are really hurting" because of the security.

"I don't see where tightening security at airports to the level where they are now is really going to accomplish much," said McGuire. "We've been waiting six months for (Iraqi President) Saddam Hussein's people to show up, and they're not here yet."