TEHRAN: Iran is being hit by a “war” on its economy, according to officials facing tightened US sanctions and renewed Israeli threats of imminent military action over Tehran's nuclear activities.

“This is war,” Ayatollah Ahmad Janati, the hardline chief of Iran’s influential Guardians Council, said as he led Friday prayers in Tehran.

Iran needs to mobilise “the nation, government, officials and armed forces”to tackle its “special and serious economic problems” which went beyond the global economic malaise, he said.

“We should prepare and break this wave (of economic pressure). We should not surrender,” he said.

Janati said officials under the supervision of Iran's supreme leader Ayatollah Ali Khamenei were tackling the crisis, and he urged national media to avoid “pessimistic” stories and instead focus on news that “make people happy, hopeful and boost their morale.”

The United States ramped up sanctions this week with a congressional measure to punish companies doing business with Iran’s energy and oil shipping sector, and an order by President Barack Obama targeting Iran’s oil exports and one Chinese and one Iraqi bank alleged to be fronting Iranian banking transactions.

Existing Western sanctions, especially an EU embargo, are already taking their toll, nearly halving Iran crude sales, according to an International Energy Agency estimate.

China, the biggest buyer of oil still exported, has lashed out at the new US sanctions.

But Obama's spokesman said on Wednesday that while the sanctions are having “a significant effect,” Iran had “yet to make the choice it needs to make, which is to abandon its nuclear weapons ambitions.”

The United States alleges Iran is seeking to develop a nuclear weapon “break-out” capacity.

Tehran denies the charge, saying its atomic programme is exclusively peaceful.

Israeli Prime Minister Benjamin Netanyahu has renewed a threat to attack Iran’s nuclear facilities.

Netanyahu told visiting US Defence Secretary Leon Panetta on Wednesday: “However forceful our statements, they have not convinced Iran that we are serious about stopping them.”

He noted that sanctions, and deadlocked negotiations between Iran and world powers, have not had “any impact on Iran's nuclear weapons program.”

Khamenei last week underlined that, under the Western pressure, “not only will we not revise our calculations, but we will continue on our path with greater confidence.”

President Mahmoud Ahmadinejad confirmed that when he said Iran had 11,000 uranium enrichment centrifuges operating, hundreds more than reported in a May 25 report by the UN’s International Atomic Energy Agency.