In remarks seemingly aimed at Israel, the US said yesterday it had “eyes” and “visibility” inside Iran’s nuclear programme and would know if Tehran made a “breakout” towards a nuclear weapon.

Washington also indicated it had not changed its view that Iran was not yet on the verge of building a nuclear bomb, despite Israeli Defence Minister Ehud Barak’s statement that US intelligence now viewed the threat as more “urgent”.

The latest signs of differing public stances from the US and its ally on Iran came on a day when speculation ran rampant in the Israeli press about a possible strike against Iran’s nuclear installations within months.

White House spokesman Jay Carney declined to comment on intelligence matters but claimed that Washington and Israel were agreed about Iran’s ambitions for its nuclear program.

“I would also say that we have eyes - we have visibility into the programme, and we would know if and when Iran made what’s called a breakout move towards acquiring a weapon.”

Breakout capability is commonly understood to be the point when a state acquires the knowledge, capability and materials to build a nuclear bomb if it wants to.

Carney said later in his briefing that he was referring to International Atomic Energy Agency officials mandated to inspect Iran’s nuclear sites because Tehran is a signatory to the Nuclear Non-Proliferation Treaty (NPT).

But many experts believe there has also been substantial infiltration and sabotage of Iran’s nuclear programme by Western and Israeli intelligence agencies.

Military sites in Iran that do not have confirmed nuclear activities are off-limits to inspectors unless provided for by agreement.

Though the Obama administration has not taken the military option off the table, Carney said “there is time and space to pursue the diplomatic option that includes extremely and increasingly aggressive sanctions”.

National Security Council spokesman Tommy Vietor, meanwhile, said that Washington continued “to assess that Iran is not on the verge of achieving a nuclear weapon”.

US officials have declined to comment directly on Barak’s remarks following a prolonged period of uneasy interaction between the Obama White House and Prime Minister Benjamin Netanyahu’s government.

But Carney’s comments appeared to be an indirect repudiation of Barak’s comment on Israeli Public Radio that it was getting tougher to assess Iran’s nuclear progress.