German mail company Deutsche Post has inadvertently issued stamps bearing the image of Adolf Hitler's former deputy, Rudolf Hess, the company said.
Deutsche Post printed 20 stamps with Hess next to a bouquet of flowers as part of a service which allows clients to order custom-made envelopes, a company spokesman said.
"It is very unfortunate. But it happened," the spokesman said. "I presume it came from the far-right scene. But those 20 envelopes won't shake up German democracy."
The stamps would be offensive to Jewish groups and embarrassing to Germans anxious to live down the country's Nazi past.
The company said it would make every effort to avoid a repeat of the incident.
The Hess blunder was not the first time customers had tried to order stamps commemorating Nazi leaders, the spokesman said.
Earlier this year, the company intercepted a request to have stamps printed featuring Hitler as a small child, he said.
The latest delivery stemmed from a private order made in March, a few weeks before Hess' birthday, he added.
Hess, who served as Hitler's deputy before he flew to Britain in 1941 on an apparent peace mission, was tried at Nuremberg for war crimes and sentenced to life in Berlin's Spandau prison.
He was the only prisoner in the vast complex for the last 21 years and was guarded by jailers from occupying Allied powers until he committed suicide in 1987 aged 93.