Iran is "over a year or so" from getting a nuclear bomb, US President Barack Obama has told an Israeli television channel, a week before visiting Israel, warning that a military option remained on the table.
In an interview with Channel 2 on Thursday, Obama laid out a clear timeline for Tehran to acquire a military nuclear capacity, while insisting that Washington would not wait until the last minute to take action to stop it.
"We think that it would take over a year or so for Iran to actually develop a nuclear weapon, but obviously, we don't want to cut it too close," he told the private station.
Obama is due to arrive in Israel on March 20 for a three-day visit, his first since being elected president in 2008. He will also travel to the Palestinian territories.
Addressing the UN in September, Binyamin Netanyahu, the Israeli prime minister, set a "red line" of spring or summer for when Iran would be close to weapons capability, suggesting prospects for an Israeli attack around that time.
But Iran's latest talks with world powers, plus adjustments in Tehran's uranium enrichment processes, are widely thought to have pushed back that deadline.
Should diplomacy fail, all options remained "on the table" for stopping Iran, Obama said.
"My message to [Netanyahu] will be the same as before: if we can resolve it diplomatically, that's a more lasting solution," he said.
"But if not, I continue to keep all options on the table."
Asked if there was a realistic option that he would order an attack on Iran's nuclear sites, he said: "When I say that all options are on the table, all options are on the table and the United States obviously has significant capabilities.
"But our goal here is to make sure that Iran does not possess a nuclear weapon that could threaten Israel or could trigger an arms race in the region - that would be extraordinarily dangerous at a time when obviously there are already a lot of things going on," he said.
Washington, Israel and much of the West believe that Iran's nuclear programme of uranium enrichment is a cover for a weapons drive, a charge denied by Tehran.
Netanyahu has said the question of Iran would be a top priority in his talks with Obama in Jerusalem.
Israel is widely believed to possess nuclear weapons but has never confirmed or denied this.