21.   As the mediator, the United States is now probing to see if Israeli security concerns are balanced by a desire to keep the whole negotiations process going.

22.   As the United States continues to control a larger share of the market, security concerns spread.

23.   Ashcroft sent a memorandum to all federal agencies requesting they limit access to public records if there is any question of national security concerns.

24.   At a time when the United States is focused on terrorism, Biden hopes to use the hearing on Wednesday to draw attention to AIDS as a security concern.

25.   As the struggle in Afghanistan moves into a diplomatic phase and terrorism declines, however, national security concerns are being replaced by concerns about economic security at home.

26.   At a Senate hearing on the issue in March, even witnesses raising the security concerns acknowledged the conflicts.

27.   As they roll down the highway, many long-haul passengers are impervious to security concerns, perhaps because they are consumed by more personal problems.

28.   At a Senate Judiciary subcommittee hearing, Ziglar said that the security concerns focused on foreign visitors, not immigrants.

29.   At the last moment, the government canceled the trip, citing security concerns.

30.   Authorities stopped admitting refugees for seven weeks last fall, citing security concerns.