The United States consulate in the Italian city of Milan was reportedly evacuated on Tuesday due to a bomb scare, according to Italy's Agenzia Nazionale Stampa Associata (ANSA).
The move came in response to a suspicious mailing, said Agence-France Press, citing Italian media sources.
An officer with Italy's counterterrorism force told the Associated Press on the condition of anonymity that the letter in question bore a symbol previously associated with Italian anarchists.
The US consulate is on Milan's Via Principe Amedeo, close to a main shopping area, and nearby buildings were also evacuated.
The news comes as America is on heightened alert, having shut down 19 diplomatic posts in Middle Eastern and African countries in response to a possible terrorist threat from Al Qaeda.
No other information was immediately available.