WASHINGTON — Secretary of State Mike Pompeo was off to Europe on Thursday to seek support and a potential diplomatic climb-down to ease rising tensions between the U.S. and Iran.

Even as the Trump administration revels in its "maximum pressure" campaign against Iran, Pompeo is traveling to Germany, Switzerland, the Netherlands and Britain to assure European leaders that the U.S. is not looking for conflict, press them to do what they can to cool the situation, and perhaps open a channel of communication with the Islamic Republic.

After a brief stop in Berlin on Friday to make up for a meeting with German Chancellor Angela Merkel that he abruptly called off earlier this month to fly to Iraq, Pompeo will make an unusual and extended stop in Switzerland, the country that has long represented Washington's interests in Tehran 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 and comes amid public signals from President Donald Trump that he wants to talk with Iran.

"If they want to talk, I'm available," Trump said last Friday, even as Pompeo and hawkish national security adviser John Bolton have stepped up warnings that any attack on American interests by Iran or its proxies will draw a rapid and significant response from bolstered U.S. forces in the Mideast. Bolton, in the United Arab Emirates earlier this week, blamed Iran for recent sabotage to tankers in the Gulf and attacks on Saudi Arabia's oil infrastructure by Yemeni rebels it backs.

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 stops in Montreaux for the annual meeting of the secretive Bilderberg Group of global influencers and in the town of Bellinzona for talks with the Swiss foreign minister, offers an opportunity to explore the possibility.

"There are only a few countries that have the trust of both Tehran and Washington," said Karim Sadjipour, an Iran expert at the Carnegie Endowment for International Peace. "Oman is one of them and Switzerland is the other."

Both channels are well-known, and Pompeo's trip to Switzerland follows a call he made two weeks ago to the Sultan of Oman, who just days later dispatched his top diplomat to Tehran for a meeting with Iranian Foreign Minister Mohammed Javad Zarif. Oman was the mediator and host of secret U.S.-Iran talks during the Obama administration that ultimately led to the 2015 nuclear deal.