US Secretary of State Mike Pompeo met with the EU's top diplomat in Brussels on Friday, a day after Vice President Mike Pence accused America's traditional European allies of trying to undermine US sanctions against Iran.
The meeting with Federica Mogherini, the EU's foreign policy chief, was scheduled before Pence's rebuke of European powers during a Middle East peace conference in Warsaw on Thursday, which Ms Mogherini skipped citing a scheduling conflict at NATO.
Ms Mogherini, who helped seal the 2015 nuclear deal between Iran and world powers, greeted Mr Pompeo in front of a bank of cameras at the EU's headquarters in Brussels before they headed into a conference room for the breakfast meeting, which was scheduled to last about an hour.
Ms Mogherini shook her head and waved off a question from the media about what she thought of Mr Pence's speech in Warsaw on Thursday, where he accused the European Union of trying to break the impact of US economic sanctions on Iran.
Mr Pence's unusually tough words for allies Germany, France and Britain reflect Washington's strategy to try to isolate Iran, in remarks that were likely to further strain transatlantic relations.
Mr Trump last year pulled the United States out of the 2015 Iran deal, under which Tehran agreed to curbs on its nuclear programme in return for the lifting of sanctions.
On Thursday, speaking at NATO before Mr Pence's comments, Ms Mogherini said the United States and the European Union had "different views" on the Iran nuclear deal and said upholding it was critical to European security because it prevented Tehran from developing a nuclear weapon.
European countries say they share Washington's concerns about Iran's involvement in wars in Yemen and Syria but believe withdrawing from the nuclear deal was a mistake, and have promised to try to salvage the deal as long as Iran continues to abide by it. In practice, European companies have accepted new US sanctions on Iran and abandoned plans to invest there.
France, Germany and Britain agreed in January to open a new channel for non-dollar trade with Iran to avert US sanctions, through a Special Purpose Vehicle (SPV) meant to help match Iranian oil and gas exports against purchases of EU goods.
However, the trade vehicle will likely take months to become operational and diplomats said it will be used only for smaller trade, for example of humanitarian products or food.