The US will unleash its “toughest ever” 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.
The demonstrations took place on the 39th anniversary of the occupation of the US embassy in Tehran, which led to four decades of mutual hostility.
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.”
What started this?
Washington is re-imposing the sanctions after Mr 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.
“That’s the goal, that’s the mission, and that’s what we will achieve on behalf of the president.”
What could the impact be?
The US has been gradually re-imposing sanctions, but analysts say this latest round is by far the most significant.
In addition, the Brussels-based Swift network for making international payments is expected to cut off links with targeted Iranian institutions, isolating Iran from the international financial system.
How have EU states reacted?
The UK, Germany and France – which are among the five countries still committed to the nuclear pact – have all objected to the sanctions.
They have promised to support European firms that do “legitimate business” with Iran and have set up an alternative payment mechanism – or Special Purpose Vehicle (SPV) – that will help companies trade without facing US penalties.
And in recent days US Treasury Secretary Steven Mnuchin said the US would “aggressively” target any firm or organisation “evading our sanctions”.
Who is exempt?
The Trump administration has granted exemptions to eight countries to continue importing Iranian oil, without naming them.
They are reported to include US allies Italy, India, Japan and South Korea, along with Turkey, China and India.
Mr Pompeo said the countries had already made “significant reductions in their crude oil exports” but needed “a little bit more time to get to zero”.
He said two would eventually stop imports and the other six greatly reduce them.
What has the reaction been in Iran?
The US sanctions are timed to coincide with the siege of the US embassy on 4 November 1979 , which took place soon after the fall of the US-backed shah.
Some 52 Americans were held hostage in the embassy for 444 days and the two countries have been enemies ever since.
Hardliners hold protests to commemorate the siege every year but on Sunday, protestors also vented their fury about the sanctions.
It followed a fiery speech from Ayatollah Khamenei on Saturday, in which he warned the US would not “re-establish the domination” it had over Iran before 1979.
However, some Iranians have taken to Twitter to vent their frustration with the regime, with the hashtag #Sorry_US_Embassy_Siege attracting more than 19,000 tweets.