Police will be deployed to inspect trucks at checkpoints around the main Federal Reserve building at Constitution Avenue NW in response to a terror alert for financial institutions in Washington, New York City and Newark, the Department of Homeland Security announced last night.

Checkpoints will be located on Constitution Avenue at 20th and 21st streets NW and on Virginia Avenue at C and 21st streets NW during daylight hours, said Thomas J. Lockwood, director of the Department of Homeland Security's Office of National Capital Region Coordination, although he said it was unclear when they would begin.

The announcement came as authorities struggled to control the impact of the terror alert in the nation's capital. A proposal to bar trucks from 15th Street NW near the Treasury Department spurred the highest-level regionwide conference yesterday among federal, District and state homeland security leaders since the alert was raised Sunday.

In addition to the hour-long meeting, the Secret Service discussed protective measures on the east side of the White House complex with Mayor Anthony A. Williams's administration, seeking to avoid a domino effect of excessive security limits in the nation's capital, said federal law enforcement and homeland security officials.

Tony Bullock, a spokesman for Williams (D), said last night that the Secret Service will close the sidewalk facing the Treasury headquarters. An agency spokeswoman, Ann Roman, said no decision had been made. Two other people briefed on the discussions said authorities were inclined to stop short of banning trucks.

The announcement of new security measures came even as Washington's top law enforcement officials said they knew of no imminent threat to the city. Homeland Security Secretary Tom Ridge on Sunday specifically identified the International Monetary Fund and the World Bank as potential targets in Washington, but he gave no indication of the timing of a possible attack.

D.C. Police Chief Charles H. Ramsey said yesterday that no additional threats have emerged. "There was nothing new about the Capitol or the White House," he said.

Referring to the erection of barricades this week on Capitol Hill and the proposal for 15th Street, Ramsey said: "There was nothing in the information to cause the kind of reaction we have with street closings and checkpoints. There is not an imminent threat, other than the fact that we believe D.C. and New York City have been on top of the target list and people already know that."

U.S. Capitol Police Chief Terrance W. Gainer also said the intelligence that prompted the alert was limited. "Beyond what Secretary Ridge has said, there is no specific intelligence about an imminent strike in Washington," he said. "There is not some other secret piece of intelligence about an imminent threat. There is not some smoking gun."

The Federal Reserve and Treasury Department developments came a day after Capitol Police closed First Street NE and set up more than a dozen checkpoints on Capitol Hill, part of the increasing fortification of Washington landmarks against a possible truck bomb attack.

According to the federal planning body for the capital region, more than 20 federal agencies are seeking to set up barrier walls, fences, concrete bollards, hydraulic gates, guard booths or other hardened perimeters.

For instance, the National Park Service is building a 35-inch-high vehicle barrier in a ring extending 50 feet to 100 feet from the Lincoln Memorial as part of $7 million road project. The Park Service is contemplating a wider buffer, as much as several hundred feet, around the Jefferson Memorial.

The Smithsonian Institution has completed a $20 million, architecturally sensitive plan to erect low barrier walls and gatehouses at 10 museums on the Mall by 2008. Defenses would include a visitor-friendly rock garden at the Museum of Natural History doubling as an anti-car barrier.

Other plans would secure an off-site Pentagon delivery facility, control vehicles for the State Department, harden the headquarters of the Government Accountability Office and fence the National Arboretum.

"Virtually all of them at this point are blast-related," said Christine Saum, director of urban design and plan review for the National Capital Planning Commission, which reviews the requests.

"No one wants to deny a security risk, but we want to make sure they are valid and thorough," Saum said.

The panel exists to preserve public spaces and is campaigning for uniform, high-quality security designs, she said. Out of about 150 applications the commission receives each year, security projects have grown from 1 to 2 percent before the Sept. 11, 2001, terrorist attacks to 15 percent last year and to 30 percent this year, Saum said.

Other officials note that federal agency heads have to act on their own to improve security because there is no federal clearinghouse that provides technical blast studies, suggests standard countermeasures or sets funding priorities.

The lack of coordination was on display this week at both ends of Pennsylvania Avenue. On Tuesday, Congress implemented the street closure and checkpoints, at a projected cost of $3 million a month, without conferring with city officials. That prompted the Treasury Department to consider unilaterally heightening its own security.

Concerned that hasty decisions would encourage other agencies to commit to a frenzy of additional closures or restrictions, Lockwood called "a timeout."

Participants in a conference call included Gainer, Ramsey, City Administrator Robert C. Bobb, Secret Service Deputy Assistant Director James E. McDermond, representatives of other federal agencies, representatives of the IMF and the World Bank and Virginia and Maryland homeland security advisers, Lockwood said.

"I wanted everybody to take a step back and understand the implication of the individual actions taken," Lockwood said. "The purpose was to change the tone where people were very reactive."

District leaders have assailed what they called the opportunistic encroachment on city streets by a security lobby taking advantage of the threatening climate. They warned that federal officials are carving a city renowned for its physical symbolism into sterile enclaves.

"You can't close major arteries in a city and expect there will be no problem," Williams said.

On the second day of increased security on Capitol Hill, no major problems were reported.

During yesterday's rush hour, lines of vehicles about 10 deep stopped at a three-lane checkpoint at Maryland Avenue and Second Street NE. Vehicles were stopped briefly and sent on their way.

Washington commuters, largely accustomed to dealing with heavy security measures, seemed undisturbed by the stops.

Dana Duncan, 27, who works on Capitol Hill, waited about two minutes in line. Duncan shrugged her shoulders when asked if the increased security measures put a damper on her morning commute. "It's a necessary evil," Duncan said. "I'd rather be safe than sorry."

Senate Sergeant-at-Arms William H. Pickle agreed.

"We don't want to disrupt traffic, disrupt lives, hurt the District of Columbia or the economy," Pickle said. "However, when you weigh everything, you have to come down on the side of life and safety."

Staff writers Dan Eggen, Nicole Fuller and Dana Priest contributed to this report.

Officials have proposed barring truck traffic from 15th Street NW near the Treasury Building and closing the sidewalk in front of the building.