Iran's President Hassan Rouhani has met with Germany's top diplomat amid heightened tensions over the country's unravelling nuclear accord with world powers.
Maas's visit to Tehran is part of European efforts to save the historic 2015 nuclear deal with Iran, and ease heightened tensions with the United States.
The U.S. pulled out of the deal over a year ago, and recently has imposed heavy new sanctions on Iran. In May, Tehran said it would begin enriching uranium closer to weapons grade if Europe didn't come up with new terms for the deal by July 7.
The tensions between the long-time rivals recently soared when the U.S. deployed an aircraft carrier and B-52 bombers to the Persian Gulf.
Iran's foreign minister has again threatened the United States over what he describes as an "economic war" launched by Washington against Tehran.
Mohammad Javad Zarif said on Monday that the U.S. "cannot expect to stay safe" after launching its economic war.
Zarif said: "Mr. Trump himself has announced that the U.S. has launched an economic war against Iran. The only solution for reducing tensions in this region is stopping that economic war."
Zarif's comments came during a news conference with visiting German Foreign Minister Heiko Maas, who had traveled to Tehran in an effort to ease tensions.
Iran's foreign minister is warning amid tensions between Washington and Tehran that "whoever starts a war with us will not be the one who finishes it."
Mohammad Javad Zarif made the remarks on Monday, speaking alongside visiting German Foreign Minister Heiko Maas.
Maas is in Tehran in an effort to salvage Iran's 2015 nuclear deal with world powers. Germany is a signatory to the accord.
Zarif came out to a news conference in Tehran grim-faced after a long private discussion with Maas, who on Sunday called Iran's ballistic missile program problematic.
The U.S. pulled out of Iran's nuclear deal over a year ago. That's the root of the current tensions with Iran. In May, Tehran said it would begin enriching uranium closer to weapons grade if Europe didn't come up with new terms for the deal by July 7.
Iran's Foreign Ministry says nothing else but the country's landmark 2015 nuclear deal with world powers will be discussed during high-stakes diplomacy meetings in Tehran this week.
Iranian state television quotes spokesman, Abbas Mousavi, as saying that visiting "European officials are not in a position to comment on Iran's issues beyond the nuclear deal."
The remarks came after German Foreign Minister Heiko Maas called Iran's ballistic missile program problematic during a visit Sunday to the United Arab Emirates.
Maas is now in Iran amid heightened tensions between Washington and Tehran. The tensions recently soared over America deploying an aircraft carrier and B-52 bombers to the Persian Gulf over a still-unexplained threat it perceives from Tehran.
After Maas, Japanese Prime Minister Shinzo Abe will arrive on Wednesday in Iran.