"If the JCPOA (nuclear deal) is supposed to continue, it was a good start and it has sent an important political message, but this is not the end of the work," Mohammad Javad Zarif told reporters on his flight back to Tehran, according to state news agency IRNA.

"From next week, intensive expert meetings will start in Europe. They must do the work, but they will consult us so that we are sure the actions they take are sufficient from our point of view," he added.

Zarif was returning from a diplomatic tour of the remaining parties to the 2015 nuclear agreement -- Britain, France, Germany, China and Russia -- following the US decision last week to pull out.

He met his European counterparts in Brussels on Tuesday.

"They said that they would ensure Iran enjoys the benefits of the JCPOA and they accepted that the implementation of the JCPOA has nothing to do with other issues," he said, referring to Iran's demand that talks on saving the deal must not be linked to pressure on its missile programme and regional interventions.

EU foreign policy chief Federica Mogherini said Tuesday that experts had already begun work on measures to get round US sanctions, focusing on nine key areas including Iran's ability to continue selling oil and gas products, and how to protect European companies doing business in the country.

"We are not fantasising that Europe will break its relations with America... but we want Europeans to defend their own interests," Zarif added.

He said the negative global reaction to Washington's withdrawal from the nuclear agreement -- and the new sanctions it announced Tuesday on Iran's central bank -- reflected US isolation on the Iran issue.

"America is not in charge of everything in the world. Of course, Americans would like the whole world to think this way and when the world doesn't think this way, they take some angry actions such as sanctioning the head of the central bank without any reason," Zarif said.

"We must expect more such moves by the Americans. These moves are against the law, contrary to conventional international relations and indicate their weakness."