The State Department reminded U.S. citizens "to remain vigilant
with regard to their personal security" while traveling abroad.
Supplementing a previous "worldwide caution," the department
said it was not responding to any particular threat but "continues
to receive reports that prompt concern" about the safety of U.S.
It advised U.S. citizens to "keep a low profile, vary routes and
times for all required travel and treat mail from unfamiliar
sources with suspicion."