"The lifting of some sanctions can, in the true sense of the word, translate into their good will. Americans talk about it, but it should be known that what happens on paper is good but not enough," Hossein Amir-Abdollahian was quoted as saying by ISNA news agency.

The US State Department on Friday said it was waiving sanctions on Iran's civilian nuclear programme in a technical step necessary to return to the 2015 nuclear agreement.

The waiver allows other countries and companies to participate in Iran's civilian nuclear programme without triggering US sanctions on them, in the name of promoting safety and non-proliferation.

Iran's civilian programme includes increasing stockpiles of enriched uranium.

The step came as talks to restore the 2015 Joint Comprehensive Plan of Action, or JCPOA, which then president Donald Trump unilaterally withdrew from in 2018, were at an advanced stage.

Amir-Abdollahian reiterated that one of the "main issues" in the talks is obtaining guarantees that the US will not withdraw from the 2015 deal again.

"We seek and demand guarantees in the political, legal and economic sectors," he said, adding that "agreements have been reached in some areas".

The Vienna talks, which include Iran, the United States, Britain, China, France, Germany and Russia, are at a stage where the parties have to make important "political decisions", different parties to the negotiations said last week.

"Our negotiating team in the Vienna talks is seriously pursuing obtaining tangible guarantees from the West to fulfil their commitments," Amir-Abdollahian said.

Earlier on Saturday, Iranian foreign ministry spokesman Saeed Khatibzadeh said: "Naturally, Tehran is carefully considering any action that is in the right direction of fulfilling the obligations of the JCPOA", local media reported.

Talks on reviving the nuclear deal were halted last week and the negotiators returned to their capitals for consultations.