BRUSSELS — Iran and the other signatories of the 2015 nuclear deal resumed negotiations in Vienna on Thursday to revive the accord, though the atmosphere was fraught in the aftermath of the apparent Israeli attack on a major uranium enrichment site in Iran.
Senior diplomats involved in the talks have agreed that the working groups meant to bring both Iran and the United States into compliance with the deal had made progress.
But after the meeting on Thursday, the head of China’s delegation, Wang Qun, called for a faster pace and fewer distractions.
“We do think that all these developments have reinforced our conviction that what is needed most now as a top priority is to do away with any disruptive factors and pick up the pace of negotiation here,” said Mr. Wang, China’s ambassador to the International Atomic Energy Agency.
said in a Twitter post that the “general impression is positive.” He said this meeting would be followed “by a number of informal meetings in different formats, including at expert level.”
The talks have been overshadowed in recent days by Iran’s response to an attack at its Natanz uranium-enrichment facility on Sunday. Tehran decided to further increase enrichment to 60 percent, a major step toward the 90 percent enrichment that is considered suitable for a nuclear bomb and a flagrant breach of the limits of the 2015 accord. Iran also said it would replace damaged centrifuges at the Natanz facility with more advanced models that were banned under the accord.
The Natanz attack was said to have been carried out by Israel, which has regularly criticized the 2015 deal as weak and unlikely to restrain Iran’s nuclear ambitions. U.S. officials have said Israel was responsible for the attack and have denied any American involvement.