US sanctions on Iran come into force

The United States will unleash its sanctions against Iran on Monday following a wave of protests across the oil-rich country. The Trump administration is reinstating all sanctions removed under the 2015 nuclear deal, targeting both Iran and states that trade with it.

It will hit oil exports, shipping and banks, all core parts of the economy.

Taking effect Monday, the measures are the most concrete result yet of US President Donald Trump's controversial decision in May to abandon the multi-nation nuclear deal with Tehran.

They will directly affect companies from third countries doing business with Iran. They could upset world oil markets, though the US has granted temporary waivers to eight jurisdictions to continue importing Iranian oil.

Iran's supreme leader Ayatollah Ali Khamenei denounced the measures on Saturday, saying Trump had "disgraced" US prestige and would be the ultimate loser in the long-running quarrel between the countries.

The US side was unmoved.

"Sanctions from the United States will be reimposed at midnight tonight," Pompeo told news channel. He said what he called "the terror regime" in Tehran must change its ways.

Before travelling to a campaign rally for the US mid-term elections, President Donald Trump said Iran was already struggling under his administration's policies.

"The Iran sanctions are very strong. They are the strongest sanctions we've ever imposed. And we'll see what happens with Iran, but they're not doing very well, I can tell you."

Washington is re-imposing the sanctions after US President Donald Trump in May pulled out of a 2015 accord aimed at curbing Iran's nuclear ambitions.

Washington also says it wants to stop what it calls Tehran's "malign" activities including cyber attacks, ballistic missile tests, and support for terror groups and militias in the Middle East.

"We are working diligently to make sure we support the Iranian people and that we direct our activity towards ensuring that the Islamic Republic of Iran's malign behaviour is changed," US Secretary of State, Mike Pompeo, told Fox News Sunday.

"That's the goal, that's the mission, and that's what we will achieve on behalf of the president."