Iran's foreign minister on April 10 said Washington is "imposing new conditions" in the negotiations to restore the 2015 nuclear agreement.

"On the issue of lifting sanctions, [the US is] interested in proposing and imposing new conditions outside the negotiations," state news agency IRNA quoted Hossein Amir-Abdollahian as saying. "In the last two or three weeks, the American side has made excessive demands that contradict some paragraphs of the text."

"[Washington keeps] talking about the need for direct negotiations, but we have not seen the benefit of direct talks with the United States," he said. "We seek the lifting of sanctions, but with dignity and with a lasting agreement," the foreign minister said, adding that "Iran has stood and will stand by its red lines".

The Vienna negotiations have been paused since March 11 after Russia demanded guarantees that Western sanctions imposed over the Ukraine conflict would not damage its trade with Iran. Days later, Moscow said it had received the necessary guarantees.