U.S. Secretary of State, Mike Pompeo, left, and German Chancellor Angela Merkel, right, address the media during a joint statement prior to a meeting at the chancellery in Berlin, Germany, Friday, May 31, 2019. (AP Photo/Michael Sohn)

BERN, Switzerland - U.S. Secretary of State Mike Pompeo brought the Trump administration's campaign against Iran to Europe for the third time this month amid heightened Mideast tensions and a risk of open conflict that has unnerved American allies.

As the Middle East buzzed with bellicose rhetoric between Iran and its U.S.-backed Gulf Arab neighbours, Pompeo was in Germany and Switzerland making the case that Washington is not looking for war and wants help in cooling the situation. But he says the U.S. will not relent on a punishing U.S. sanctions campaign targeting Iran.

Coming after President Donald Trump on Thursday renewed his willingness to talk with Iran's leadership, Pompeo's trip has raised speculation that the administration may be looking to open a channel of communication with the Islamic Republic.

Germany sent a senior diplomat to Iran earlier this week and Switzerland has long represented U.S. interests there.

Pompeo's Iran-related diplomacy has already taken him to Iraq, Britain, Belgium and Russia since early May. That's when tensions flared after U.S. allegations of increased threats from Iran that have now led to additional military deployments and accusations that Iranian proxies sabotaged oil tankers in the Gulf and conducted drone attacks in Saudi Arabia.

On Friday, it coincided with Saudi calls for Iranian aggression to be dealt with firmly and the release of the U.N. atomic watchdog's quarterly report on Iran's compliance with the 2015 nuclear deal. Trump withdrew the U.S. from the deal last year and has steadily reinstated sanctions on Iran, sparking protests from Tehran, which has threatened to walk away itself from the deal.

The report from the International Atomic Energy Agency in Vienna said Iran continued to stay within the limitations set by the 2015 deal but for the first time raised questions about its adherence to a key provision intended to limit the country's use of advanced centrifuges that can enrich uranium. The seriousness of the issue was not immediately clear, although a senior diplomat said discussions were ongoing about how to resolve the matter.

U.S. officials had no immediate comment on the IAEA report but the question about Iranian compliance was likely to bolster Pompeo's case for a tough stance as he opened his European tour in Germany, which along with Britain and France, remains a party to the Iran deal.

Pompeo met Chancellor Angela Merkel a day after she delivered not-so-veiled criticism of Trump in a commencement speech to Harvard University.

Without directly naming Trump, Merkel told Harvard graduates that they should "tear down walls of ignorance" and reject isolationism as they tackle global problems. She also said leaders should not "describe lies as truth and truth as lies."

Merkel said before the meeting with Pompeo they would discuss how to prevent Iran from getting nuclear weapons and "how we prevent other aggressive actions by Iran."

After talks with German Foreign Minister Heiko Maas, Pompeo said Washington will not stand in the way of a system Europeans are developing to shield companies dealing with Iran from American sanctions, so long as it provides only humanitarian and other permitted goods.

Pompeo said the U.S. does not take issue with the system known as INSTEX, so long as it deals with goods not subject to sanctions.

"When we think about INSTEX, if it's aimed at facilitating the movement of goods that are authorized to move, it's unproblematic," he said.

From Berlin, Pompeo travelled to Switzerland, for an unusual and extended stop in the country that represents the United States diplomatically in Iran and has in the past been an intermediary between the two. His three days in Bern will be the first visit to the Swiss capital by a secretary of state in more than two decades.

U.S. officials have downplayed speculation that Pompeo will use his time in Switzerland to try to open a direct line to the Iranians.

But the Bern visit, along with day trips to Montreux for the annual meeting of the secretive Bilderberg Group of global influencers and to the southern Alpine town of Bellinzona for talks with the Swiss foreign minister, offers an opportunity to explore the possibility.

Pompeo leaves Switzerland on Monday to attend an entrepreneurship conference in The Hague, Netherlands, and then will join Trump in London on the president's state visit to Britain.

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Rising reported from Berlin. Associated Press writer Geir Moulson contributed to this report.

News from © The Associated Press, 2019