Iran’s foreign minister has warned the US it “cannot expect to stay safe” after launching what he described as an economic war against Tehran.

Speaking alongside the German foreign minister in Tehran on Monday, Javad Zarif said Iran would not start a war but “whoever starts a war with us will not be the one who finishes it”.

He also set the bar high for any talks with the US, saying: “President Trump himself has announced that the US has launched an economic war against Iran. The only solution for reducing tensions in this region is stopping that economic war.”

The bilateral talks with his German counterpart, Heiko Maas, were described as frank by Zarif, normally a sign that the two countries did not reach common ground. Germany is the lead country in Europe trying to set up a special purpose vehicle (SPV) to ease trade between Europe and Iran without falling foul of US economic sanctions. Iran has repeatedly urged the European Union to make the SPV operational, arguing increased trade with Iran was integral to its efforts to win domestic support for the nuclear deal signed in 2015.

The US withdrew from the nuclear deal in May last 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.

Maas said Germany and its European partners had “made the greatest effort to meet [their] commitments”, but in the face of threatened US sanctions against European companies that trade with Iran, said they could not perform miracles.

Maas acknowledged the economic benefits Tehran hoped for from the deal were now “more difficult to obtain”. But he urged Iran not to go ahead with planned graduated steps to reduce its commitments to the deal, but instead to fully to respect the agreement. It is in Iran’s “political and strategic interest to maintain this agreement and the dialogue with Europe”, he said.

Tehran is due to take further steps to leave the deal on 7 July, when it says it will increase its level of uranium enrichment over the limits agreed in the 2015 nuclear deal.

Defending Iran’s regional foreign policy from claims it has been disruptive, Zarif turned the tables by asking a series of questions largely aimed at Saudi Arabia’s foreign policy. “Was it us that gave arms to Saddam Hussein? Did we support al-Qaida? Did we imprison the prime minister of Lebanon? Are we bombing Yemeni civilians every day? Did we support Isis and the Jabhat al-Nusra in Syria, or were American weapons provided by Saudi Arabia?”

He also urged European countries to wean themselves off the dollar as the chief currency for international trade. “America’s power rests on the dollar; a great part of America’s economic power will go away if countries eliminate the dollar from their economic systems,” he said.

Later this week the Japanese prime minister, Shinzō Abe, will meet the Iranian president, Hassan Rouhani, amid speculation Abe might act as a message carrier between Tehran and Washington on any steps that could be taken to reduce tensions. Abe is close to Trump, but has not supported the US decision to pull out of the nuclear deal, and might be able to act as a broker for talks.

“In a further call for calm, the UN’s nuclear watchdog said on Monday it was “worried about increasing tensions” over Iran’s nuclear programme, after Tehran said it might stop respecting more elements of a 2015 international deal.

“I ... hope that ways can be found to reduce current tensions through dialogue,” International Atomic Energy Agency director general Yukiya Amano said in a speech opening the agency’s quarterly board meeting.

The IAEA said Iran was increasing its stocks of enriched uranium, as it had threatened to do a month ago, but the watchdog could not calculate by what date these stockpiles would breach the limits set in the nuclear agreement.