A man who entered the US embassy in Berlin, punched a security guard and claimed his suitcase contained a bomb was arrested on Friday, but experts aided by a police robot found no explosives.
Embassy personnel alerted the authorities after the man - identified by police as a 23-year-old German national - entered the premises, said he wanted to have his US passport renewed and punched a security guard after being given an alternate address.
As police were taking the man into custody, he claimed his suitcase contained a bomb, an embassy spokesman said. But experts who examined it with the help of a police robot only found some personal effects.
A police spokesman the man was still in custody and investigations were ongoing. A decision would be taken on whether he should remain in custody, be released or receive psychological attention.
Police declined to confirm a report from newspaper Bild that the man was seeking revenge for the death of Osama bin Laden, the al-Qaeda leader killed in a May 2011 US raid on his hideout in Pakistan.
Berlin's Pariser Platz, where the embassy and the city's iconic Brandenburg Gate are located, was cordoned off and later reopened. The US embassy is one of the German capital's most closely guarded buildings.