A hundred prominent Germans, including business leaders, ministers and top sports stars, on Sunday urged Iran to free two journalists who interviewed the son of a woman sentenced to death by stoning.
The appeal was published by Bild am Sonntag weekly for whom the two unnamed journalists work.
"The pair must be released and must return to Germany as soon as possible," said Foreign Minister Guido Westerwelle.
"A state like Iran, which always calls for understanding, must not flout it in other areas," added Defence Minister Karl-Theodor zu Guttenberg.
Other signatories included the heads of Deutsche Bank, Deutsche Telekom and BMW, footballer Philipp Lahm, Formula One star and seven-time former world champion Michael Schumacher and Nobel literature laureate Herta Mueller.
The two journalists were arrested on October 10 in Tabriz for interviewing the son and family lawyer of Sakineh Mohammadi Ashtiani, the woman sentenced to death.
Iran says the two Germans entered the country on tourist visas and failed to obtain the necessary accreditation for journalists from the authorities before "posing as reporters" when they contacted Mohammadi Ashtiani's family.
Mohammadi Ashtiani was sentenced to death by two different courts in Tabriz in separate trials in 2006.
Her sentence to hang for her involvement in the murder of her husband was commuted to a 10-year jail term by an appeals court in 2007.
But a second sentence to death by stoning on charges of adultery levelled over several relationships, notably with the man convicted of her husband's murder, was upheld by another appeals court the same year.