Foreign Minister Mohammad Javad Zarif says Iran could increase uranium enrichment should the European Union continue to act passively in the wake of the US withdrawal from the Iran nuclear deal.

"The Europeans and the other signatories must act in order to compensate for the effects of the US sanctions," Zarif told the German news magazine Der Spiegel on Saturday.

The US withdrew from the 2015 agreement in May and began reimposing sanctions on Iran at the start of August, with further sanctions on the country's finance and energy sectors to follow on November 4.

Zarif said Tehran might act if "the balance of give and take were destroyed," adding that "oil and banks" were the litmus test. This, however, did not necessarily mean that Iran would for its part withdraw from the nuclear agreement.

Partial or reduced implementation was another possibility, Zarif asserted.

The foreign minister said European parties to the nuclear deal with Iran must decide if they want to submit to US pressure, adding the Europeans needed to decide whether they are ready to let deeds follow their words.

"The Europeans and the other signatories must act in order to compensate for the effects of the US sanctions," he said.

The EU has invariably opposed the US withdrawal, calling the deal a pillar of regional and international peace and security.

Tehran has tasked the European signatories - the UK, France, Russia, and Germany - to make their continued commitments to the deal worthwhile by guaranteeing that the country continued to benefit from the economic rewards of the deal.

Zarif also rejected direct talks with US President Donald Trump. He said Iran would only think about talks with the United States if the US returned to the nuclear deal.