In a Friday press release, the department announced that Pompeo would leave on Sunday for a two-day trip to Moscow and Sochi, where the State secretary will meet with Putin and Russian Foreign minister Sergey Lavrov.
"No one wants Iran to be in possession of a nuclear bomb".
Pompeo was coming to Brussels to discuss pressing matters, including Iran, with European officials, State Department spokesman Morgan Ortagus said.
European powers said they would "reject any ultimatums", after Iranian President Hassan Rouhani last week gave them 60 days to ease the impact of sanctions imposed in the oil and banking sector in particular.
Separately on Monday, Mogherini chaired a meeting of the so-called E3 - Britain, France and Germany - to discuss efforts to keep the nuclear deal going, including a special trade mechanism called Instex the trio set up to try to enable legitimate trade with Iran to continue without falling foul of USA sanctions.
European Union foreign affairs chief Federica Mogherini said on Monday that European Union member states continue "to fully support the nuclear deal with Iran" ahead of a foreign ministers summit in Brussels.
Doris Day, Iconic Singer & Actress, Dead At 97
Doris was also a singer and performed the hit song " Que Sera, Sera ", and she was a famed animal rights activist. Her screen partnership with Rock Hudson was one of the biggest box-office draws of the 1950s and '60s.
Iran said this week it would partially end its compliance with the deal unless European nations are able to circumvent the sanctions and provide it with benefits it was due under the accord, from which Trump withdrew past year. He plans to meet Russian President Vladimir Putin and Russian Foreign Minister Sergei Lavrov in the Black Sea resort of Sochi on Tuesday.
Mogherini said the talks would focus on "how to continue to best support the full implementation of the nuclear deal".
The highest-level talks in 10 months, the meeting comes as the two top world powers are at odds over Venezuela, Ukraine, North Korea, Iran and Syria, to name several hard issues that will be on the agenda.
The deal - originally signed by the United States, the European Union, the five permanent members of the UN security council and Iran to halt the latter's nuclear advancements - was already in bad shape, after the USA past year made a decision to unilaterally withdraw from it.
Jeremy Hunt, the foreign secretary, expressed alarm over the danger of stumbling into war as tensions escalated between Iran and the United States after the unexplained "sabotage" of vessels, including Saudi oil tankers, in the Gulf. "This is already the most unstable region in the world and this would be a massive step in the wrong direction". It comes as the Europeans struggle to keep financial supply lines open to Iran to offset the impact of USA sanctions on the Islamic republic's shattered economy.
His warning comes less than a week after a significant shift in the dynamic between the USA and Iran saw Washington deploy forces in the Gulf. This will be the highest-level talks between the USA and Russian Federation in 10 months.