Iran says it will take another step away from a 2015 nuclear deal by starting to develop centrifuges to speed up its uranium enrichment but it also gave European powers two more months to try to save the multilateral pact.
Separately, the United States refused to ease its economic sanctions on Iran, imposed fresh ones designed to choke off the smuggling of Iranian oil and rebuffed, but did not rule out, a French plan to give Tehran a $US15 billion ($A22.3 billion) credit line.
The moves suggested Iran, the United States and the major European powers may be leaving the door open for diplomacy to try resolve a dispute over Iran’s nuclear program even as they largely stuck to entrenched positions.
The friction has intensified since US President Donald Trump last year withdrew from the 2015 international accord under which Iran had agreed to rein in its atomic program in exchange for relief from economic sanctions.
Washington has since renewed and intensified its sanctions, slashing Iran’s crude oil sales by more than 80 per cent.
Trump again said he was open to the possibility of meeting Iranian President Hassan Rouhani but made clear he had no intention of easing sanctions.
“That’s not happening,” he said. “That won’t be happening.”