"We know that the economic advantages promised by Iran with this agreement are to be realized in the scope of hard to without the Americans", said Maas.
Tehran, meanwhile, announced that it would partially suspend its commitments under the nuclear deal, having set a 60-day deadline for the five remaining signatories to the deal - Russia, China, the UK, France, and Germany - to ensure that Iranian interests are protected or else the country would resume enriching uranium at higher levels.
"I'll say it again: We won't allow Iran to develop nuclear weapons that will endanger us and the entire world", he said.
"We have said it clearly that economic war is not different from a (military) war at all".
In his meeting with Maas, President Hassan Rouhani blamed the United States for the soaring tension and called on the European signatories of the deal to "resist the economic war on Iran imposed by America".
Most recently, the Trump administration sent USA warships to the Persian Gulf and continued to pile on even more sanctions.
"The common target of Iran, Germany and European Union is preserving JCPOA and preventing tensions in the region, as well as having the Iranian nation benefit from the JCPOA advantages", he said in statements cited by the semi-official Mehr news agency.
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The officers who arrested Golunov last week have been suspended pending an investigation, Kolokoltsev said . Shortly after his arrest, police published photographs that they said showed a drug lab at his rented flat.
His trip comes at a critical time for the Joint Comprehensive Plan of Action (JCPOA), a 2015 agreement on Iran's civil nuclear program between Tehran and a group of six world powers (not including Japan).
Abbas Mousavi, spokesperson for the Iranian Foreign Ministry asserted, "The EU is not in a position to question Iran's issues beyond the nuclear deal".
The US withdrew from the nuclear deal in May previous year and is imposing a policy of maximum economic pressure to cut trade with Iran and reduce its oil exports, the lifeblood of the Iranian economy.
Last month, Japan formally expressed its concern over the mounting tensions in the Persian Gulf in hastily convened talks in Tokyo held between Abe and Iran's Foreign Minister Mohammad Javad Zarif.
European nations had pledged to create a mechanism called INSTEX, which would allow Iran to continue to trade for humanitarian goods despite American sanctions. "The Iranian nation has proved during this period that it will resist against pressure and bullying", PressTV cited him as saying.
INSTEX, or Instrument in Support of Trade Exchanges, was created to facilitate trade between France, Germany and the United Kingdom with Iran to bypass the reimposed U.S. sanctions.
Iran insists its nuclear activities are entirely peaceful and has repeatedly refused to discuss its missile program.
Enriched uranium is used to make reactor fuel but also nuclear weapons, while spent fuel from a heavy-water reactor contains plutonium that would be suitable for a bomb.