THE TERROR ALERT issued by the US State Department on Sunday has frustrated Americans planning to travel within Europe because of its vagueness.

US citizens have been warned to “be aware of their surroundings” particularly when travelling on metros, railways, aircraft, ships or any “tourist infrastructure” within Europe.

Americans have been told to “adopt appropriate safety measures to protect themselves when traveling” within the continent because of the threat of a suspected Al Qaeda attack.

However, travelers have not been given any specific information about the nature of the suspected attack, the cities that may be targeted, or even the countries that may be marked for a terror attack.

Intelligence analysts have said that they have issued the alert based on credible but not specific information.

Bruce Hoffman, a terrorism expert at Georgetown University, told the New York Times that the alert was not particularly useful:

Usually they’re at least country-specific. This one is an entire continent. I’m not sure what it says, beyond the fact that the world’s a dangerous place, and we already knew that.

However, Frank J Cilluffo, a former Bush administration homeland security official now at George Washington University, said that the decision to issue an alert was appropriate:

I err on the side of sharing the information, since a vigilant citizenry can help prevent an attack.