"It seems there really is a report by US intelligence agencies. I don't know if it's by the National Intelligence Estimate or a different agency circulating between senior chambers," he told public radio, asked about the report which Israeli daily Haaretz ran on its front page.

"As far as we know, it brings the American assessment much much closer to ours," Barak said. "I'd say that compared to previous American appraisals, it makes the Iranian issue a bit more urgent."

Israel, the sole if undeclared nuclear power in the Middle East, says Iran's nuclear programme poses an existential threat to it, and has repeatedly refused to rule out military action to halt Tehran's nuclear activity.

Iran refuses to bow to Western demands that it curb its sensitive uranium enrichment under the pressure of punishing economic sanctions that were ramped up in July to their toughest level so far.

Tehran is demanding that its "right" to enrichment be recognised and that the sanctions be eased.

The Islamic republic rejects Western suspicions that it is seeking a nuclear weapons capability, insisting its nuclear ambitions are entirely peaceful.

A series of visits by high-ranking US defence officials to Israel raised speculation that Washington was trying to dissuade Israel from a preemptive military attack.

"We are determined to prevent Iran from becoming nuclear, and all the options are on the table. When we say it, we mean it," Barak said.

"When the Americans say it, 'We believe them', others should believe them too," the defence minister said.