21.  At one point Friday, government officials said they had acquired information pointing to a possible attack on the Sears Tower in Chicago.

22.  Avoiding the offending substance is by far the best way to cope with a possible anaphylactic attack.

23.  At the same time, the Yugoslav army moved thousands of troops closer to Kosovo, fearing a possible NATO attack.

24.  Barak said the actions could encourage possible terrorist attacks against Israelis and he ordered additional security forces on alert.

25.  Black-clad security officials roamed the roof of the White House, scanning the skies for a possible attack.

26.  -- Troops set up checkpoints on roads leading into Moscow, an action officials said was to guard against possible attacks by Chechen terrorists.

27.  A lack of warning means that a possible attack must be feared constantly.

28.  A nationwide alert for a possible terrorist attack was temporarily relegated to secondary priority, and police concentrated most of their efforts on helping motorists.

29.  A possible attempted attack on Camp David.

30.  A senior official of a foreign intelligence service also confirmed Monday night that his service had received the reports of a possible terrorist attack in Nairobi.