Law enforcement agencies said yesterday that they will inspect vehicles for explosives around the International Monetary Fund and World Bank buildings, as well as downtown Washington and on Capitol Hill, while maintaining police patrols citywide to safeguard against possible attacks on other targets.

D.C. police said they have activated surveillance cameras trained on areas near the IMF and World Bank headquarters in Northwest Washington, just off Pennsylvania Avenue about two blocks from the White House. Authorities also said teams of bomb-sniffing dogs are sweeping the vicinity.

Police officials said there were no immediate plans to close streets as a result of Homeland Security Secretary Tom Ridge's announcement of an orange alert -- one rung below the highest level -- for the financial institutions in Washington as well as New York and Newark. Residents, workers and motorists near the IMF and World Bank and elsewhere should expect disruptions, they said, although they added that they hoped to keep inconvenience to a minimum.

"We will be more aggressive in making traffic stops of cars, trucks and limos," D.C. Police Chief Charles H. Ramsey said in an interview. "We have to pay attention to just about anything that could be explosive or chemical."

Tony Bullock, spokesman for Mayor Anthony A. Williams (D), said the security effort also will focus on other federal buildings that "are significant to financial markets in the country." Those include the Federal Reserve, the Department of Commerce, the Securities and Exchange Commission and the Bureau of Engraving and Printing.

He said officials will consider "whether there will be a need for some street or Metro closures due to the proximity of tunnels and air shafts to certain buildings."

After yesterday's federal announcement, the Williams administration and D.C. police raised the city's terrorism threat level one category to orange, strengthening security and identification checks at government buildings and mobilizing more personnel. A Special Threat Action Team of 200 police officers trained to respond to terrorist attacks is on standby.

Police officials plan to meet this morning with security officials from both institutions and will also discuss security measures with other financial organizations, such as banks, Ramsey said. "Even though the threat was specific to the IMF and the World Bank, you can imagine that other institutions are going to be concerned," he said. "If you harden one target, you make another soft."

World Bank spokesman Damian Milverton said that the FBI, Secret Service and D.C. police "are increasing their support to us as the bank enhances its security measures in response to the threat alert. There have been no specific threats against the bank, however, and we will be open for business as usual Monday."

Although D.C. officials acknowledged that the threat was the most specific and credible against the nation's capital since the Sept. 11, 2001, terrorist attack on the Pentagon, they urged people to go about their routines, while taking care to be highly vigilant and to review their emergency preparedness plans.

"If you go to work around these buildings, if you are going to go shopping, if you are going to have friends for dinner, go about your business. This is our way of life. This is our strength," Williams said.

Williams and Ramsey urged people to notify authorities of suspicious activity, including strangers photographing possible targets and people or vehicles making unusual movements. The mayor said that police will have the necessary staffing to respond to such calls without reducing community patrols.

Dozens of federal law enforcement agencies are coordinating security measures at high-priority sites, including the White House, the Capitol and the State Department.

U.S. Capitol Police Chief Terrance W. Gainer said security checks for cars and trucks on Capitol Hill will increase today, affecting traffic specifically on and near Independence and Constitution avenues and First, Second and Third streets.

After a noon teleconference with federal and local law enforcement officials, Gainer said he decided to assign his officers to 12-hour shifts, with only one day off each week.

Law enforcement officials said the announcement itself was one of the best defenses against attack, possibly prompting terrorists to change their plans. "We seek to disrupt whatever plans and operations they have. That is the whole goal here," Ramsey said.

Ridge's announcement set off a flurry of activity in Washington, New York and Newark. While heavily armed police took up positions around the Prudential Insurance Co. in Newark and New York City officials said that heavily army squads would bar some trucks from some of its bridges, D.C. police sought to maintain a lower profile.

"We're not in competition with New York. We're responding to the threat information that we have," Ramsey said.

New York City officials, in business attire, held a news conference shortly after Ridge's 2 p.m. television appearance. District leaders held their news conference at 5 p.m., with emergency officials dressed in such attire as polo shirts, shorts and sneakers.

D.C. officials said Ridge contacted Williams on Saturday night after ABC News reported that New York City had already announced an increase in its security posture in response to a threat. Williams said only that communication from the federal government could be improved.

Homeland Security officials said they received the information about the Washington sites later than the information about New York. They said it was refined overnight before the decision was made yesterday to raise alert levels. Homeland Security officials said that New York had more targets, in larger skyscrapers, in denser city blocks. The IMF and World Bank are smaller and easier to secure, officials said.

In a joint statement, Virginia Gov. Mark R. Warner (D) and Maryland Gov. Robert L. Ehrlich Jr. (R) sought to reassure residents, noting that threat levels in their states were not raised.

In the District, Matt Nehmer, spokesman for George Washington University, near the IMF, said the campus advisory Web site and emergency information phone line were updated within an hour of Ridge's news conference.

"The university is open and operating on a regular schedule," Nehmer said, adding that he learned about the new threat level from TV.

George Ronetz, general manager of Kinkead's restaurant, several blocks west of the IMF and the World Bank, said some customers started changing their dinner plans soon after Ridge's briefing.

"We are already getting cancellations from people who are asking about street closures and other things related to the threat level," Ronetz said. But, he added, "we are going to stay open. . . . We live life as normally as possible."

Staff writers Del Quentin Wilber, Hamil R. Harris, Sari Horwitz and Lyndsey Layton and staff researcher Don Pohlman contributed to this report.

Homeland Security Secretary Tom Ridge's announcement marked the first time specific locations were noted.Metro Transit Officer Eric Croom and Coda patrol the McPherson Square station during their shift, which was extended after the orange alert.Dozens of federal agencies are coordinating security measures at high-priority sites, including the White House.