The U.S. embassy has ordered increased security for American facilities in Germany, in response to what officials call a heightened threat situation.

An embassy statement issued Friday urged Americans in Germany to use increased vigilance and take steps to ensure their own personal security.

Embassy officials did not specify the nature of the threat, but they said U.S. facilities constantly assess their security postures in response to a heightened threat environment.

A spokesman for the embassy noted that German authorities have warned of an increased threat of terrorism against their country because of its participation in the NATO military mission in Afghanistan.

Some information for this report was provided by AP and Reuters.