US sanctions Iran's foreign minister Mohammad Javad Zarif

Donald Trump last night escalated tensions with Iran by putting sanctions on its foreign minister Mohammad Javad Zarif.

The United States called Mr Zarif a "propaganda minister not a foreign minister" and said he was "implementing the reckless agenda of Iran’s supreme leader".

The sanctions effectively shut out Iran's top diplomat, freezing any assets of Mr Zarif in the United States, and is likely to curtail his international travel.

US officials indicated he would still be able to travel to and from the United Nations in New York, and said they had not asked allies to stop talking to him.

The blacklisting of Iran’s chief negotiator could hinder any US attempt to use diplomacy to resolve its disagreements with Tehran over Iran’s nuclear programme, and its aggressive activities in the Middle East.

However, the US did not close the door on potential nuclear talks, saying that they considered Mr Zarif to not be a significant decision maker.

It was unclear whether Mr Zarif had any assets in US jurisdiction that would be affected by the sanctions.

Mr Zarif responded to the news on Twitter, saying: "The US reason for designating me is that I am Iran's 'primary spokesperson around the world'. Is the truth really that painful?

"It has no effect on me or my family, as I have no property or interests outside of Iran. Thank you for considering me such a huge threat to your agenda."

Tensions between the US and Iran have soared recently because of attacks on tankers in the Gulf, and Iran’s downing of a US drone.

Last month Steve Mncuhin, the US treasury secretary, indicated Mr Zarif would be blacklisted.

However, it it was believed at that point Mike Pompeo, the US secretary of state, was among those against the move.

Following the decision, a senior US official said: "President Trump decided enough is enough. He is sending a clear message to the regime its recent behaviour is completely unacceptable.

"For far too long Zarif has had this veneer, not great, of being the reasonable interlocutor for the Iranian regime. He is no such thing.

"He implements the reckless policy of the supreme leader, and he is the regime's primary spokesman around the world."

The official added: "The US has historically placed faith in diplomacy but there are limits to our patience when a nation so routinely flouts these protocols."

He said a number of factors had been taken into consideration including Mr Zarif's defence of the execution of gay people.

The official said: "Zarif was the point of contact for nuclear negotiation for the previous administration. We do not consider him to be our primary point of contact. He would not be the president's selected point of contact."