WASHINGTON -- President Clinton ordered security tightened at federal installations across the country yesterday after a powerful bomb ripped apart an Oklahoma City federal building and cast a nervous pall over the government work force.
Increased security was evident at the Capitol and the vice president's house, as well as at the White House, where for the first time in memory handbags and lunches that were being carried into the complex were X-rayed.
Jittery officials evacuated more than a dozen government buildings across the country in response to telephoned threats or suspicions that something was amiss.
The Social Security Administration shut down its 18 offices in Oklahoma two hours after the blast and stepped up security measures elsewhere.
One of the agency's field offices was on the ground floor of the building that was devastated by what investigators described as a car bomb weighing perhaps 1,000 to 1,200 pounds.
Late yesterday afternoon, 15 of the 61 Social Security employees who were at work when the bomb went off were unaccounted for, said Phil Gambino, the agency's spokesman. All worked in the front of the office, closest to the blast, where there also was a public waiting room with 30 to 40 people.
About 550 people reportedly worked in the building.
"We are taking every precaution to reassure and to protect people who work in or live near other federal facilities," Mr. Clinton said in a televised statement yesterday.
The devastating blast raised anew concerns about terrorism and assured new examinations of security provisions in federal buildings across the country.
Rep. Jim Ross Lightfoot, chairman of an appropriations subcommittee that handles the budgets of a number of federal agencies, said he plans to hold hearings.
"This situation is unprecedented in its magnitude and type of destruction," the Iowa Republican said. "The whole purpose of federal buildings is to give the public access to federal [agencies]. That means they have to be open so people can wander in and out of them.
"Terrorist activities are the most difficult to defend against -- and most ghastly because of the innocent lives lost. The main thing is not to panic because that's the whole purpose of a terrorist attack."
John Sturdivant, president of the American Federation of Government Employees, which represents many federal workers, was less restrained. "No effort is too extreme to guarantee the safety of federal employees."
All over Washington, federal workers huddled in front of television sets to watch for the latest news on the bombing. Many said they were not only worried about the danger of a similar attack here but also concerned about whether colleagues in Oklahoma City were among the victims.
"We've got a lot of people going in and out of Oklahoma City," said Rick Atkins, a Federal Aviation Administration employee. "I'm just worried about FAA people there," he said. The agency's offices in Oklahoma City are not in the building where the blast occurred.
A few blocks away, Transportation Department workers gathered in front of television sets in the cafeteria. Some said they were not completely shocked by yesterday's attack, after the 1993 bombing at the World Trade Center in New York and other terrorist attacks around the world.
The blast didn't seem to affect the annual spring tourist boom. Swarms of visitors lined up at the steps of the Capitol while thousands of workers and visitors lunched and rested under shady trees along the Mall.
The Capitol was last closed for security reasons in November 1983, when a bomb blew a hole in a wall outside the Senate chamber. No one was hurt, and two leftist radicals pleaded guilty.
Although the building has not been closed since then, security was intensified in the wake of that bombing and includes barriers designed to prevent a bomb-laden car from getting close to the building.
A group of students visiting from Carlisle, Ark., said the mood at the Capitol was starkly different from what it was on Tuesday.
"Yesterday, when we came here, things were a lot different," said Joe Calvert of Carlisle.
hTC "Today, the police took their time looking through our stuff when we walked in, and it seemed like there were more police all over the Mall."
A Boston-area family waiting for a tour of the FBI building will go home disappointed tomorrow. The FBI canceled its tours for the day after news reports of two bomb threats that could not be confirmed.
"This was going to be my big tour," said Dan Jenkins, who had been touring Washington with his family all week.
The FBI also strung security tape around the building to limit access and reportedly closed two entrances.
Across the country, other federal workers were uneasy.
"I know if I am, other people are," said Larry Burns, chief deputy of the U.S. Marshal's Office in South Bend, Ind., whose office manages security for five federal courthouses.
"We are scared to death," said Elizabeth Horne, an employee at the Indianapolis federal building.
Responding to telephone bomb threats, authorities emptied government buildings in New York; Detroit; Omaha, Neb.; Wilmington, Del.; Dallas; Fort Worth, Texas; Boise, Idaho; Portland, Ore.; Cincinnati; Dayton, Ohio; Steubenville, Ohio; Fresno, Calif.; East Palo Alto, Calif.; Riverside, Calif.; and Santa Ana, Calif.
In Boston, a federal building and City Hall were evacuated after "certain doors and things that should have been locked were found to be open," said Bob Dunfey, regional administrator for the General Services Administration.