European powers vowed to keep the 2015 nuclear deal alive without the United States by trying to keep Iran’s oil and investment flowing, but admitted they would struggle to provide the guarantees Tehran seeks.

Speaking after the meeting on Tuesday, EU foreign policy chief Federica Mogherini told a news conference the meeting had been positive with all parties agreeing on ‘lines of actions and measures to put in place’ after U.S. President Donald Trump’s decision.

Mogherini said Europe remained committed to implement the accord reached by Iran, the EU, China, Russia, France, Germany, Britain and the U.S. in 2015.

Iranian foreign minister Mohammad Javad Zarif said the meeting had been a good start, but he wanted to see guarantees materialize.