A U.S. newsite reported that Israel has shared with the U.S. administration and many European allies in intelligence over the past two weeks that Iran was taking technical measures to prepare for 90 percent purity uranium enrichment, a level that would allow it to continue producing a nuclear bomb in no time.

Axios' correspondent in Tel Aviv, Barak David, passed on this information from "two updated American sources."

The information provided by the reporter indicates that the preparatory measures mentioned will allow Iran to continue enriching uranium to 90 percent "within weeks" if it so chooses.

The source said that Israeli intelligence analysts estimate that the Iranians may do so soon, in an attempt to gain influence in the nuclear talks in Vienna, which resumed on Monday.

The U.S. source said Israel has further told its allies in the West that new Iranian intentions may push it to step up attacks against U.S. forces and interests in the region, through its missions in Yemen, Syria and Iraq.

The renewal of the nuclear deal being negotiated in Vienna limits the level of enrichment that Iran can enrich uranium to 3.67 percent, well below the 90 percent needed for weapons, or to 20 percent that Iran reached before the agreement. Iran is now enriching uranium at various levels, the highest being about 60 percent.

The Israeli warnings come with the resumption of nuclear talks after a 5-month hiatus, in light of an atmosphere that was considered "positive", although analysts do not see much chance of reviving the agreement signed in 2015.

The meeting, which began the new round of talks, lasted just over two hours at the Coburg Palace in Austria, where the historic agreement was reached, according to AFP.

The head of the EU negotiating delegation, Enrique Moreh, said during a press conference that he was optimistic about the first day of talks, but did not believe a breakthrough would be achieved in the first round.

He said experts would continue to work over the next few days on a "sense of urgency to revive the 2015 agreement," but declined to give a deadline because the issues at stake are "complex."

The meetings come as Israel continues to persuade Washington to take a tougher stance on the nuclear deal with Iran.

Israeli Defense Minister Benny Gantz said Monday that Israel had shared with its allies "intelligence indicating Iran's continued race toward nuclear weapons."

Foreign Minister Yair Lapid, who met with his British counterpart Liz Truss in London on Monday, talked about intelligence that Iran intends to continue its nuclear program "secretly" regardless of the results of the negotiations in Vienna, according to the American news site Axius.

Gantz is expected to visit Washington in the coming days to discuss the nuclear crisis with US Secretary of Defense Lloyd Austin and other senior members of President Joe Biden's administration.

The Jerusalem Post reported Monday that the IDF is preparing "Plan B" if the talks fail, and that the military continues to "refine its capabilities to launch a military offensive" on Iran, "if circumstances so require."