Mogherini rebuked Trump in a forceful statement, noting that the U.S. did not have any right to unilaterally cancel the Iran agreement | Sean Gallup/Getty Images Mogherini to fly to Washington amid rift with Trump over Iran EU ministers express deep concern over US president’s stance.

LUXEMBOURG — The EU's top diplomat, Federica Mogherini, will fly to Washington to address the sharp disagreement between European powers and U.S. President Donald Trump over the Iran nuclear accord.

Mogherini announced her trip to the U.S. capital as EU foreign ministers, meeting in Luxembourg on Monday, expressed deep concerns over Trump's refusal to certify Iran's compliance with the terms of the deal, and his request that Congress adopt new "triggers" that would reimpose sanctions on Tehran.

French Foreign Minister Jean-Yves Le Drian, speaking to reporters on his way to the meeting, called on the EU to exert "pressure on Congress ... so that the American Congress does not call this agreement into question.”

Mogherini rebuked Trump in a forceful statement on Friday, in which she noted that the U.S. does not have any right to unilaterally cancel the Iran agreement, known as the Joint Comprehensive Plan of Action (JCPOA). French President Emmanuel Macron, German Chancellor Angela Merkel and U.K. Prime Minister Theresa May also issued a statement reiterating their support for the deal.

While European leaders have disagreed sharply with Trump before — notably on his decision to withdraw from the Paris climate accord — the dispute over the Iran nuclear agreement represents a remarkable break among NATO allies on a crucial security issue.

The 2015 Iran deal was brokered by three European countries — France, Germany and the U.K. — as well as the U.S., Russia and China.

At their meeting in Luxembourg, EU foreign ministers issued a joint statement expressing complete support for the deal, which lifted most sanctions against Tehran in exchange for curbs on Iran's nuclear program.

The EU “is committed to the continued full and effective implementation of all parts of the JCPOA,” the ministers said.

In their statement, the ministers suggested a willingness to impose new punitive measures on Iran if warranted on other issues, but only outside of the nuclear agreement. "While the EU expresses its concerns related to ballistic missiles and increasing tensions in the region, it reiterates the need to address them outside the JCPOA, in the relevant formats and fora,” the ministers said.

EU leaders are expected to issue their own statement on Iran in the formal conclusions of this week's European Council summit meeting in Brussels. A statement by the leaders on North Korea is also expected in the conclusions, officials said.

Privately, however, officials in Luxembourg said they had little interest in kowtowing to the Americans, and they expressed growing annoyance with Trump.

Mogherini noted that further action against Iran was not on Monday's agenda. "We didn't discuss and we are not discussing further restrictions on Iran," she said.

The foreign ministers stressed Europe was united behind the Iran deal, which has been positively assessed by the International Atomic Energy Agency (IAEA). In the first year after its implementation, trade between the EU and Iran increased by 79 percent.

Some ministers expressed disbelief at Trump's apparent desire to dismantle the achievements of his predecessor, Barack Obama.

“It looks like the priorities of the U.S. president is to destroy everything that has been accomplished by the previous president, like the health care system, the Paris agreement, and now this very important Iran deal,” German Foreign Minister Sigmar Gabriel told reporters.

Others warned that a more isolationist America would end up strengthening Russia. “If it will be more isolationist it will cut the transatlantic ties, so not only Russia will be stronger but all unhelpful forces will be stronger,” Lithuanian Foreign Minister Linas Linkevičius told POLITICO in an interview.

Linkevičius, however, underlined that there was still room for dialogue and he tried to express optimism that the gap with Washington could be bridged.

“It's part of my job description to be optimistic," he said.