President Clinton is ordering immediate improvements in security at federal office buildings following a Justice Department finding that most facilities fail to meet new standards adopted after the Oklahoma City bombing.

Under the new standards, the devastated Alfred P. Murrah Federal Building in Oklahoma City would have had shatterproof exterior glass and security for adjacent street parking, Deputy Attorney General Jamie Gorelick said at a news conference Wednesday.Of 347 large federal office buildings that were part of the study, just 15 percent X-ray incoming packages and mail; less than half have parking controls that meet the new standards; and only a quarter have visitor and employee identification and control systems, the Justice Department reported.

Clinton issued a memo saying that "all executive branch agencies shall immediately begin upgrading their facilities to meet the recommended minimum security standards."

The new standards will add 5 percent to the cost of a new building, while improving security at existing buildings will be costly as well, Gorelick said.