Top US officials will tell their Israeli counterparts on Tuesday that the Biden administration remains committed to diplomacy with Iran, but if necessary would be prepared to pursue "other avenues" to ensure Tehran does not acquire a nuclear weapon, a senior US official said.
A visit to Washington by Israel's national security adviser, Eyal Hulata, will allow the two allies to share intelligence and develop a "baseline assessment" of how far Tehran's nuclear programme has advanced, the official said.
Under a 2015 deal, Iran curbed its uranium enrichment programme, a possible pathway to nuclear arms, in return for the lifting of economic sanctions. Then-US President Donald Trump quit the deal in 2018 and the Israeli government opposes US efforts to revive it.
In broad terms, US experts believe the time it would take Iran to achieve nuclear "breakout" — enough enriched uranium to build a nuclear bomb — has "gone from about 12 months down to a period of about a few months" since Trump pulled out of the pact, the official said, speaking on condition of anonymity.
"Obviously that is quite alarming," the official told reporters ahead of Hulata's talks with US national security adviser Jake Sullivan.
Iran has consistently denied it is developing nuclear weapons.
Echoing President Joe Biden's comments in a White House meeting with Israeli Prime Minister Naftali Bennett in August, the official said: "We of course remain committed to a diplomatic path."
"But obviously if that doesn't work there are other avenues to pursue, and we are fully committed to ensuring that Iran never develops a nuclear weapon."
Asked what actions were under consideration and whether that included military options, the official said "we'll be prepared to take measures that are necessary" but did not elaborate.
The official said that Iran was "sending indications to a number of parties that they are preparing to come back to Vienna", where the United States and Iran held indirect talks earlier this year that stalled.
But signalling that obstacles remain, Iran's foreign minister said on Saturday that the United States must first release $10 billion of Tehran's frozen funds as a sign of goodwill, something the Biden administration has shown no willingness to do.
Bennett, a far-right politician who ended Benjamin Netanyahu's 12-year run as prime minister in June, has made clear he wants Biden to harden his stance against Iran, Israel's regional arch-foe.
There is also disagreement over Biden's opposition to further expansion of Jewish settlements on occupied land that the Palestinians want for a future state.
Asked whether the issue would be part of Tuesday's talks, the US official said Israel was well aware of the administration's view of the need to refrain from actions that could be seen as "provocative" and undermine efforts to achieve a two-state solution between Israel and the Palestinians.