Law enforcement agencies in the District said they are prepared to be at the highest level of vigilance possible without a specific threat.

"We stepped things up a couple days ago when the rhetoric stepped up," D.C. police Executive Assistant Chief Terrance W. Gainer said about reports that Washington was among cities that may have been targeted for terrorist activity.

When the department goes to Level One, it pays special attention to cars and trucks parked near important places and buildings, the bomb squad is moved to 12-hour shifts and all intelligence officers are kept on alert, Gainer said.

In the nation's capital, however, threats are ever-present, and most agencies are routinely prepared to be extra vigilant.

The FBI prepares for potentially disastrous events all the time, said spokeswoman Elisa Foster.

The only real difference the millennium brings is a slight increase in the number of complaints the agency looks into, she said.

Senior law enforcement officials are trying to "ratchet down" an NBC report, which named Washington, Seattle and New York as possible targets for terrorists.

One official said authorities had developed a lot of intelligence over the past few weeks and that in the process a number of cities have been mentioned.

The three cities, the official noted, would almost by logic appear on a list: New York, for its celebration in Times Square; Washington, for its millennium party on the Mall; and Seattle, because that's the nexus for the Algerian connection.

Seattle's importance came to light Dec. 14, when Algerian Ahmed Ressam, 32, was arrested in Port Angeles, Wash., after bomb-making materials allegedly were found in his car.

The FBI warned yesterday that mail bombs may have been sent to the United States from Germany, prompting postal inspectors to screen parcels with Frankfurt postmarks.

The FBI has not been specific about what investigators are looking for, although every batch of packages from overseas coming into Dulles International Airport is being monitored by postal inspectors, said Doug Bem, a spokesman for the Postal Inspection Service.

U.S. Park Police, expecting that the monuments they protect might be an attractive staging area for intentional disasters, are increasing their presence, said Maj. Edward Winkel, a spokesman for the agency.

They will look for packages left near monuments, people lurking in areas closed to the public, people carrying packages and anyone acting peculiar, Winkel said.

Park Police will question those people and even pat them down if they are acting suspiciously enough, Winkel said.