21.   Authorities tightened security at federal buildings throughout the city, including the Capitol and the White House.

22.   Bill Ptacek said system security has been tightened.

23.   Beyond that, Nugent again called on network administrators everywhere to tighten security on their computers to prevent hackers from penetrating them in the first place.

24.   Both bases already are high-security facilities and have not been impelled to tighten security since the threats were made, officials said.

25.   A controversial proposal to tighten White House security is making the Clinton administration feel more vulnerable politically.

26.   A court spokeswoman, Jerrianne Hayslett, warned sternly that security may be tightened further.

27.   A bill to tighten seaport security has passed a Senate committee.

28.   A Marine exercise in Jordan was cut short, and security has been tightened at bases and ports used by U.S. forces in the region, officials said.

29.   A transfer of custody was tentatively set for Thursday morning at the Opa-locka airport outside Miami, where security was being tightened.

30.   After that, security was tightened, but the steps were nothing compared with what has been put in place in the last two months.