Iran preparing to enrich weapons-grade uranium, Israel warns U.S.

Israel has shared intelligence over the past two weeks with the U.S. and several European allies suggesting that Iran is taking technical steps to prepare to enrich uranium to 90% purity — the level needed to produce a nuclear weapon, two U.S. sources briefed on the issue tell me.

Why it matters: Enriching to 90% would bring Iran closer than ever to the nuclear threshold. The Israeli warnings come as nuclear talks resume in Vienna, with Iran returning to the negotiating table on Monday after a five-month hiatus.

State of play: Enrichment alone will not produce a bomb. Estimates vary as to how long it would take Iran to master the additional technological requirements, but U.S. and Israeli intelligence sources have put the timeline at one to two years.

Iran is already enriching uranium to 60%, far beyond the levels allowed under the 2015 nuclear deal that Donald Trump abandoned and President Biden is now attempting to salvage.

There is no civilian use for 90%-enriched uranium.

Behind the scenes: The intelligence Israel shared with the Biden administration suggests the Iranian preparatory steps would allow Iran to move ahead with 90% enrichment within weeks if it chose to do so, according to one of the U.S. sources.

Israeli intelligence analysts assess that Iran could take that dramatic step soon in an attempt to gain leverage in the Vienna talks, the source said.

Israel also shared an intelligence assessment that Iran's desire for leverage in Vienna could lead Tehran to further increase attacks against U.S. forces and interests in the region via proxies in Yemen, Syria and Iraq, the U.S. source said.

The Israeli Prime Minister’s Office, Foreign Ministry and Ministry of Defense declined to comment. The White House hadn't responded to a request for comment by time of publication.

What they're saying: Israeli officials have been pushing their U.S. and European counterparts to take a hard line with Iran in Vienna. Israeli Defense Minister Benny Gantz said in a speech on Monday that Israel had shared with its allies “intelligence which points to Iran’s continued race toward a nuclear weapon while violating the 2015 agreement."

Israeli Foreign Minister Yair Lapid, who met with his U.K. counterpart Liz Truss in London on Monday, claimed there was indisputable intelligence that Iran intended to secretly continue its nuclear program no matter the result in Vienna.

Truss called the Vienna talks “the last opportunity for the Iranians to come to the table” and agree to return to the 2015 accord. “We will look at all options if that doesn't happen," she said.

Iranian Foreign Minister Hossein Amir-Abdollahian said on Monday that the U.S. and its European allies “must understand that this opportunity is not a window that could remain open forever."

Meanwhile, Iran's hawkish new nuclear negotiator, Ali Bagheri Kani, wrote in the FT that a deal will only be possible if the U.S. is willing to "pay a price" for Trump's withdrawal, guarantee that it won't be repeated, and make the first move by removing all sanctions imposed since 2015. The Biden administration has said it will not meet those conditions.

Driving the news: The nuclear talks resumed Monday with a plenary session including the Iranian delegation and diplomats from the EU, France, Germany, the U.K., Russia and China.

The U.S. negotiating team, headed by Iran envoy Rob Malley, is in Vienna but not in the room. They'll be negotiating indirectly through European mediators.

The latest: The head of the EU delegation, Enrique Mora, said in a press briefing that he was optimistic about the first day of talks but doesn’t think any breakthrough will be reached in the initial round.

He said Iranian negotiators had agreed to take into consideration the previous six rounds of talks held under the previous, more moderate Iranian government.

Mora said Tuesday's sessions would focus on sanctions relief, Iran's top priority, and Wednesday's on the needed limitations on Iran’s nuclear program.

Bagheri said the prioritization of sanctions relief was an achievement for Iran. He also said he was optimistic.

What’s next: Gantz is expected to visit Washington in the coming days to discuss the Iranian nuclear crisis with Secretary of Defense Lloyd Austin and other senior Biden administration officials.