Though Berlin has long been known as a nest of espionage, the arrests have underscored the extent to which the sides watched each other.

The arrests also underscored the fact that the face of the drug user in the region is not always the face of an inner-city addict.

The arrest of Brian Regan underscores just how broken the clearance process has become.

Recent arrests in Europe, particularly in France and the Netherlands, have underscored the extent of the problem.

The arrest underscores how much of a haven France, with its large Arab and Muslim population, has become for Islamic militants.

The arrests underscore concern over industrial espionage at a time when new technologies have made it easier to transfer proprietary information.

The arrests of the officers underscored a wider problem examined by the Mollen Commission during its public hearings on police corruption last month.

The arrest underscored the increasing nervousness among federal counterterrorism officials about the possibility of a terrorist attack in the near future, perhaps before the November election.

Proponents of tighter immigration controls asserted that the Canadian arrests underscored the threat they said lurked just beyond American borders.

The latest arrests underscore the breadth of the problem.