The European Union's top diplomat said yesterday that the existing nuclear deal between Iran and world powers must not be sacrificed as part of any U.S. moves to forge a new security agreement with Tehran amid attempts to set up a meeting between President Donald Trump and his Iranian counterpart.

Tensions have risen sharply between Washington and Tehran since Trump unilaterally pulled the U.S. out of the nuclear agreement last year. As re-imposed and escalated U.S. sanctions kicked in, further hurting Iran's virtually moribund economy, Iran lost billions of dollars in business deals allowed by the nuclear accord. The U.S. sanctions largely blocked Tehran from selling crude abroad, a crucial source of hard currency for the country. Separately, the Islamic Republic was accused of launching attacks on a number of cargo ships in the strategic Straits of Hormuz, at the mouth of the Persian Gulf.

The EU, meanwhile, has encouraged Iran to respect the nuclear deal and has set up a system to help keep money moving into the country. Tehran, however, has increased its uranium enrichment activities after the U.S. pullout from the nuclear deal.

At a G7 summit on Monday, Trump said there's a "really good chance" he could meet Iranian President Hassan Rouhani, although Rouhani wants sanctions lifted before agreeing to such high-profile talks.

Asked at a meeting of EU foreign ministers in Finland what a possible meeting might mean for the Europeans, the bloc's foreign policy chief, Federica Mogherini, said the pact aimed at curbing Iran's nuclear ambitions is a multinational agreement enshrined in a U.N. Security Council resolution and that "what is existing needs to be preserved."

Mogherini said that if other complementary work can be done that respects the nuclear deal, "we will always be there to accompany and support this approach."

When he pulled the U.S. out of the deal, Trump said that it does nothing to stop Iran developing missiles or destabilizing the wider Middle East. The Europeans insist that it was only ever meant to stop Iran from building a nuclear bomb.

German Foreign Minister Heiko Maas said it's important for all sides to take advantage of Trump's new willingness to hold talks.

"Now it's about operationalizing that and making sure everyone makes a contribution, including Iran, which leads to de-escalation in the region," Maas told reporters.

During their talks in Helsinki, the ministers debated ways to help provide maritime security in the Straits of Hormuz, following an American appeal for countries to take part in a naval mission there. Germany has ruled out taking part, but the EU more broadly is mulling whether to play some kind of observer role.

"If there are no security risks in the straits of Hormuz then we don't need any mission. But unfortunately it's Iran who has posed the risk," said Finnish Foreign Minister Pekka Haavisto, whose country holds the EU's 6-monthly rotating presidency. Asked what the EU might do, he said only that "different ideas have been floating around."

Haavisto again urged Iran to stick by the nuclear agreement, insisting that the Islamic Republic "shouldn't play with the idea of enriching uranium and so forth."

"Europe has been their true partner," he said. "Europe is not to blame."

Dutch Foreign Minister Stef Blok said it's important to build on the new momentum from the G7 summit. "Avoiding nuclear development in the Middle East is of the utmost importance," Blok said.