Top EU diplomat Federica Mogherini has asked the US not to "interfere" in European politics.
Ms Mogherini made the remarks on the second day of a two-day visit to Washington, her first since Donald Trump became President.
"We do not interfere in US politics [...] And Europeans expect that America does not interfere in European politics," AFP quoted Ms Mogherini saying.
In January, then-US ambassador to the EU Anthony Gardner said Mr Trump was supporting the fragmentation of Europe by backing Brexit — an outcome he said would not be in America's best interests.
During Ms Mogherini's visit, she also said meetings with the Trump administration had given her confidence that the US was committed to following through with the Iran nuclear deal.
"I was reassured by what I heard in the meetings on the intention to stick to the full implementation of the agreement," Ms Mogherini told reporters a day after talks at the White House and State Department.
She said the new administration made clear it had not decided on a new American ambassador to the EU, and had also not decided on a way forward on stalled US-European trade talks.
At the start of a series of meetings with top officials, the EU's foreign affairs boss said she hoped to find "common ground" with the Trump administration.
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