WASHINGTON, May 20 -- President Clinton, dramatically enlarging the perimeter of security barriers around the White House, said Saturday he reluctantly agreed Pennsylvania Avenue 'must be closed' permanently after more than 200 years of mostly unimpeded traffic. The sudden security measures, begun shortly after dawn without formal advance notice, continued through the day with rental cranes lowering concrete barriers on the southern side of the White House. Meanwhile, young people on roller blade skates took advantage of a two-block stretch of Pennsylvania Avenue now emptied of vehicular traffic. The conversion of the highly traveled boulevard to a pedestrian-only mall is one of 11 categories of security precautions -- five of which will remain secret -- being put into effect as soon as possible, including a change in air traffic patterns in the vicinity of the White House, officials announced. Clinton's final go-ahead signal Friday night allowed authorities to order the concrete barriers across one of the busiest streets in the nation's capital,passing one of the world's most famous addresses -- 1600 Pennsylvania Avenue. The section of roadway partitioned by the new barriers is where the presidential reviewing stands had traditionally been placed for the quadrennial Inaugural Parade. The action made drive-by photography of the White House, a popular occupation of capital city tourists, impossible from most nearby vantage points. 'Pennsylvania Avenue has been been routinely open to traffic for the entire history of our Republic,' Clinton said in his weekly radio address Saturday morning after the barriers were set in place.
'Through the Civil War, through world wars, through the Gulf War it was open, but now it must be closed.' Clinton said he was following the advice of the Treasury Department, the Secret Service and of a panel of experts and 'distinguished Americans who served in past administrations of both Democratic and Republican presidents.' 'Though I am reluctant to accept any decision which might inconvenience the people who work in or visit our nation's capital I believe it would be irresponsible to ignore their considered opinion,' Clinton said. The closing 'is necessary because of the changing nature and scope of the threat of terrorist actions,' Clinton said. The response at the White House should be seen as an effort to preserve American freedoms, not to restrict them, he said, and Clinton added he still intends to 'be every bit as active and in touch with ordinary American citizens as I have been since I took office.' The blocked stretch of Pennsylvania Avenue 'will be converted to a pedestrian mall,' he said. Traffic will be rerouted in the 'least bothersome way possible.' Clinton linked the dramatic action to enlarge the perimeter of barriers around the White House to what he said was a need for American society to pull together. 'The fact that the Secret Service feels compelled to close Pennsylvania Avenue is an important reminder that we have to come together as a people and hold fast against the divisive tactics of violent extremists,' he said. 'I think it's great, walking in the middle of the street,' one tourist said as a yellow lift truck moved concrete barriers. But, she added, 'I am sure it's going to be a disadvantage' to drivers when Monday's peak traffic flow resumes. The tourist, Doris Aiazzi of Reno, Nev., like hundreds of others who were slowly strolling in front of the White House Saturday morning, would have to wait until the afternoon to walk freely in the middle of the six-lane thoroughfare, when police stopped keeping the area clear for work crews. 'I think we're seeing cowardice in its greatest form,' Bob Delaney, of Center Conway, New Hampshire, said as he walked in front of the White House Saturday. 'We've got a history of Franklin Roosevelt -- he was a helpless cripple -- he didn't have even that fence. We had Harry Truman who walked across the street' regularly, Delaney said. Delaney, who said he was a former security officer, saw a political opportunity in the day's developments for Republicans. 'Bob Dole could be sensational,' he said, referring to the Senate Majority Leader who hopes to be the GOP nominee for president in 1996. 'He could come down here and say 'The first thing I'm going to do if elected president is take this down.'' The area blocked off by four rows of concrete barriers at each end, including a row of huge concretepots filled with flowers, stretches from 15th street to 17th street. The Treasury Department as well as the Old Executive Office Building and Blair House, the official presidential visitors' quarters, share frontage on the street with the White House at that point. Also affected is LaFayette Square across the avenue from the White House, a perpetual haven for protestors, some of whom have constructed makeshift living quarters out of their signs. Court decisions allowing their continued presence have noted the proximity of their site to a public street and Clinton told a group at the White House that the street's closing will not change their status. 'They'll be able to go to LaFayette Park and protest against the president as they always have,' he said. 'Are we going to live in the world forever being scared?' Joe Cledera, visiting from the Philipines, asked as he watched the uniformed police park their patrol cars in the middle of a Pennsylvania avenue newly deprived of ordinary traffic. Gaps in the barriers were allowed to permit their movements. Pennsylvania Avenue was permanently blocked at 6 a.m., a step previously taken only on a temporary basis after various security alerts, such as the October firing of a weapon through the White House fence. Weeks of construction work will follow to replace the concrete blockades with an enclosed mall. Treasury Secretary Robert Rubin, holding a news conference after Clinton's radio address Saturday, told reporters, 'This action was taken reluctantly. The White House security review was not able to identify any alternative' to protect the White House from 'explosives carried by vehicles.' Clinton delivered his 'final concurrence' with the security recommendations Friday night, Rubin said. The White House security review made 11 recommendations approved by Clinton and Rubin, only six of which are being made public. Rubin said he personally became convinced that the closings of Pennsylvania Avenue and two small streets in the southwest corner of the White House complex were necessary after a briefing on the technical aspects of terrorist capabilities he received two weeks before the bombing of the federal building in Oklahoma City. The Oklahoma City bombing a month ago then confirmed 'the absolute necessity' of accepting the recommendations of the White House security review, Rubin said. The review was begun by Rubin's predecessor, Lloyd Bentsen, after a light plane was deliberately crash landed in darkness so close to the Executive Mansion that some debris hit the building. The pilot was killed in the Sept. 12 incident. October 29, a gunman posing as a tourist fired a high-powered rifle through the White House fence, striking the building several times and penetrating windows but injuring no one. Several other lesser security- related incidents since then were also considered as part of the security review, Rubin said. Other measures now being put into effect include a change in the civil air traffic rules that already prohibit airliners and private aircraft from approaching too close to the White House complex, as they navigate their takeoffs and landings from nearby National Airport, Rubin said. From now on the several federal and municipal law enforcement agencies which share responsibility for the security of the White House complex and its environs will be directed by a common 'memorandum of understanding,' backed up by an annual review of procedures. Any incident will have as its lead investigator the agency most expert in the type of violation, not the one with geographical responsibility, he said. The Secret Service will always have the 'operational command and control' of law enforcement reactions to emergencies and the ensuing investigations. The Treasury Department and the Defense Department will cooperate on 'sensitive security related' projects, Rubin said. 'The White House was built in another era when security concerns were not so great,' Rubin said. But the Oklahoma City bombing and that of the World Trade Center 'must remind us that the threat of terrorism is very real,' he said. The changes preserve 'access on foot,' Rubin said. And 'drive-by viewing of the White House' may still be possible, but from much farther away, across the expanse of LaFayette Square -- a view now mostly blocked by trees. Pennsylvania Avenue has been open to vehicular traffic since October 13, 1792, when the first cornerstone of the White House structure was put in place. In recent years, concrete barriers were placed next to Pennsylvania avenue in front of the White House to prevent cars and trucks from ramming the fence. Retractable metal beams were installed in the White House driveways and the gates were reinforced for the same reason. The White House itself was closed for three years, from 1814 to 1817, after it was set afire by the British in the War of 1812. A sandstone structure, it stands on 18 acres of land on the south side of Pennsylvania Avenue, between the Treasury Department and the Executive Office Building.