Congress opened its debate on war in the Persian Gulf yesterday amid heightened security in the U.S. Capitol, as law enforcement officials responded to the possibility of terrorism if America attacks Iraq.

The U.S. Capitol Police staged what a spokesman called "a show of force" on the Capitol grounds, ordering officers to patrol more often and make themselves more visible. Officers also stiffened the enforcement of standard security procedures, closing off some corridors to tourists and closely checking the credentials of staff members and reporters.

Officer Dan Nichols, a spokesman for the Capitol Police, said officers have been placed on "a heightened alert status."

"We're monitoring what's happening abroad and nationally," Nichols said. "Tensions are running high, and {the Capitol} is a difficult place to secure under the best of circumstances. We have taken some steps to increase security. Depending on what happens it may increase even more."

Nichols and other officials declined to discuss the additional security measures in detail.

A spokesman for the General Services Administration, which manages most federal buildings, said there has been no government-wide security crackdown, but that officials are monitoring events in the Persian Gulf. The spokesman said the agency has a comprehensive security plan that could be activated if necessary.