A German police bomb squad Friday destroyed a suspect letter sent to the Berlin residence of President Joachim Gauck, but the interior ministry later said no explosives were found.
Security services speaking on condition of anonymity had initially said an explosive powder had been detected in the envelope.
But an interior ministry spokeswoman said later: "The criminal police investigation has not confirmed this suspicion."
Gauck, whose post as head of state is largely ceremonial, was not at the Bellevue Palace residence at the time, and no staff were endangered, an office spokeswoman said.
The suspect letter was discovered in routine mail screening and destroyed in a controlled explosion in a remote part of the grounds of the palace in Berlin, said Gauck's office.
There had been suspicion the envelope contained HMTD, a compound often used as a detonator in the mining industry.
Gauck, 73, who was a Lutheran Christian pastor in the former communist East Germany and assumed his post as president early last year, is not considered a divisive public figure.