A number of new generation Iranian centrifuges are seen on display during Iran’s National Nuclear Energy Day in Tehran, Iran April 10, 2021. Iranian Presidency Office/WANA (West Asia News Agency)/Handout

Iran on Sunday said that it is enriching uranium to 20 percent purity using advanced centrifuges, amid an impasse in diplomatic efforts to curb the Islamic Republic’s nuclear program.

Behrouz Kamalvandi, a spokesperson for the Atomic Energy Organization of Iran, said the enriched uranium was first collected from IR-6 centrifuges on Saturday, the Associated Press reported. Iran notified the International Atomic Energy Agency (IAEA), which serves as the United Nations’ nuclear watchdog, of the move two weeks ago, he added.

Just a day earlier, a report released to member states by the IAEA verified that Iran was operating a cascade of 166 advanced IR-6 centrifuges “for the declared purpose of producing” 20 percent enriched uranium, Reuters reported.

According to the Washington, DC-based Center for Arms Control and Non-Proliferation, “enriching uranium to 20 percent represents about 90 percent of the effort needed to produce weapons grade fissile material.”

“Once a proliferator reaches this threshold, it could be ready to weaponize in a relatively short time,” the Center wrote.

On Sunday, Israeli Prime Minister Yair Lapid called on international powers to respond to Iran’s enrichment activity with the “full force” of UN Security Council sanctions. “Israel, for its part, reserves for itself full freedom of action, diplomatic and operational, in the fight against the Iranian nuclear program,” he emphasized, echoing a line reiterated by successive Israeli governments.

The United States and Iran carried out indirect talks in Qatar last month in a bid to advance stalled efforts to revive the 2015 nuclear accord, though no progress was made. Washington originally withdrew from the deal, which granted Iran substantial sanctions relief in exchange for temporary restrictions on its nuclear program, under the administration of President Donald Trump in 2018.

Iran has since violated multiple limits imposed by the accord. Last month, it began removing surveillance equipment installed by the IAEA, after the UN watchdog’s Board of Governors passed a resolution condemning Tehran for failing to explain traces of uranium detected at undeclared sites.

US officials have said that Iran has repeatedly introduced demands unrelated to the nuclear agreement during negotiations, contributing to a deadlock. Iran has denied these assertions, with its foreign minister expressing Tehran’s determination “to seek a good, strong and lasting accord.”

Robert Malley, Washington’s special envoy for Iran, acknowledged last week that Iran currently has a sufficient amount of highly enriched uranium to make a bomb, should it decide to. “It would take them a matter of weeks,” he said, noting that the US would detect such a move and “react quite forcefully.”

“To our knowledge, they have not resumed their weaponization program, which is what they would need to develop a bomb,” Malley added.