German Economy Minister Sigmar Gabriel flew to Iran Sunday as the first top Western official to visit the country since world powers and Tehran reached a historic nuclear deal.
Gabriel, who is also Chancellor Angela Merkel's deputy leader and energy minister, embarked on the three-day trip with a "small delegation of representatives from companies, industry groups and the sciences", his ministry said in a statement.
Gabriel is due to hold talks with Iranian President Hassan Rouhani and several ministers following Tuesday's landmark nuclear agreement.
The long-delayed pact "lays the foundation for normalising economic ties with Iran on the condition that the steps set out in it are now implemented", Gabriel said in the statement.
The head of the German Chambers of Commerce and Industry, Eric Schweitzer, who is accompanying Gabriel, called the trip "an encouraging sign" for companies barred from doing business with the resources-rich Gulf state due to Western sanctions.
Schweitzer called for German companies to be given legal protection for upcoming investments made in Iran in case Tehran violated the terms of the nuclear deal and a trade embargo were imposed again.
"Such a framework would give companies the necessary legal security to return to Iran," he told DPA news agency.
Iran and Germany were historically close trade partners but business dropped off as a result of the sanctions, declining to 2.4 billion euros ($2.6 billion) last year from around eight billion euros in 2003-2004, according to German figures.
Schweitzer said bilateral trade could quadruple in the next two to three years to around 10 billion euros.
- 'Inhumane regime' -
The international agreement finalised in Vienna aims to ensure the Islamic Republic does not obtain nuclear weapons.
In exchange, the country of 78 million people will be given step-by-step relief from crippling international sanctions.
German business leaders have pointed to pent-up demand in modernising Iran's industrial infrastructure, particularly in the oil sector, as presenting lucrative opportunities.
Engineering, chemical, pharmaceutical, car part and railway companies are all eyeing big contracts.
Iran has the world's fourth largest oil reserves and the second in gas, meaning it has the biggest combined energy deposits.
Iran's oil ministry has announced it intends to attract up to $100 billion of foreign investment to modernise the sector, which has been underdeveloped for a decade.
However critics called on Gabriel not to lose sight of human rights in the race to rebuild trade ties.
The Berlin-based uncle of 26-year-old Iranian Reyhaneh Jabbari, who was hanged last year for killing a former intelligence officer to ward off what she said was an attempted rape, told the Bild newspaper that Gabriel was "doing business with an inhumane regime".
"When he signs contracts, he should think about the people sitting in prisons, about the regime critics, the tortured, the condemned," Fariborz Jabbari said.
The head of the German chapter of Reporters Without Borders, Christian Mihr, told Bild it would be "disastrous" if on Gabriel's visit "economic interests were put ahead of human rights and press freedom".