Iran's foreign minister embarks on a tour of world powers on Saturday, state media reported, in what is seen as a last-ditch effort to save Tehran's nuclear deal after Washington's withdrawal from the accord.

President Donald Trump pulled the United States out of the deal on Tuesday, raising the risk of conflict in the Middle East, upsetting European allies and casting uncertainty over global oil supplies.

Iran said it would remain committed to the deal without Washington if Tehran achieved its goals - namely being protected from sanctions against key sectors of its economy such as oil - in cooperation with other countries that have signed up to the agreement.

President Hassan Rouhani said he had asked Foreign Minister Mohammad Javad Zarif to negotiate with European countries, China and Russia in the coming weeks. "If at the end of this short period we conclude that we can fully benefit from the (nuclear accord ..., the deal would remain," he said.

Zarif is due to leave for Beijing on Saturday and will later travel to Russia. He will then go to Brussels to meet counterparts from Germany, Britain and France "about the fate of the nuclear deal", Iranian state television said.

"Iran has asked the European Union and particularly Germany, France and Britain to announce as soon as possible their stand on how Iran's interests can be fulfilled and guaranteed under the nuclear agreement after America's withdrawal," the TV report said.

Europe's largest economies lobbied to protect their companies' investments in Iran on Friday, seeking to keep the nuclear deal with Tehran alive after Washington pulled out and threatened to impose sanctions on European companies.

Germany and France have significant trade links with Iran and remain committed to the nuclear agreement, as does Britain, and the three countries' foreign ministers plan to meet on Tuesday to discuss it.

That is part of a flurry of diplomatic activity following Trump's unilateral withdrawal from what he called "a horrible, one-sided deal", a move accompanied by the threat of penalties against any foreign firms doing business in Iran.