Tensions between Iran and the United States have intensified after Tehran warned the US not to threaten the country following inflammatory comments by President Donald Trump.

On Sunday, Mr Trump significantly ratcheted up hostilities with Iran by issuing a strongly worded tweet: “If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!” he said.

On Monday, Iranian foreign minister Mohammad Javad Zarif hit back, dismissing Mr Trump’s “genocidal taunts”.

“Iranians have stood tall for millennia while aggressors all gone,” he tweeted. “Try respect – it works!” He also suggested that Mr Trump was being “goaded” by members of his administration such as national security adviser John Bolton.

Mr Zarif’s comments came as Iranian media reported that the country has increased the rate of enrichment of its uranium four-fold – a week after it said it would stop meeting commitments it signed up to under the 2015 nuclear deal. The US pulled out of the deal last year, and despite European efforts to keep it intact, the landmark agreement is in danger of unravelling.

Increased enrichment

Reports said Iran had informed the United Nations of the increased enrichment, though it appeared that it had not increased the enrichment past the level stipulated in the deal.

If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again! — Donald J. Trump (@realDonaldTrump) May 19, 2019

Mr Trump said on Monday Iran would be met with “great force” if it attempted anything against US interests in the Middle East, saying Tehran has been very hostile toward Washington.

Mr Trump told reporters as he departed the White House for an event in Pennsylvania that he was willing to have talks with Iran “when they’re ready” but no discussions were happening currently.

“With Iran, we’ll see what happens,” the US president said. “But they’ve been very hostile. They’ve truly been the No 1 provocateur of terror.

“I think Iran would be making a very big mistake if they did anything. If they do something, it will be met with great force but we have no indication that they will. We’ll have no choice,” he added.

Sunday’s intervention by Mr Trump had seemed to mark a shift in tone by the president, who has sought to play down concerns about a possible conflict between the US and Iran in recent days. Asked on Friday if the US would go to war with Iran, Mr Trump replied: “I hope not.”

Ambiguity around the president’s position continued on Monday when he said in a tweet that the US had tried to open negotiations with Iran. “Iran will call us if and when they are ever ready. In the meantime, their economy continues to collapse – very sad for the Iranian people!” he said.

There have been growing indications that the US could be moving closer to conflict with Iran, after it deployed an aircraft carrier and B-52 bombers to the Persian Gulf. Secretary of state Mike Pompeo also made a surprise trip to Iraq earlier this month, while last week all non-essential staff were ordered to leave US embassies and consulates in the country. The US also withdrew waivers granted to third parties buying Iranian oil.

Attacks

Unexplained attacks against four vessels – including two owned by Saudi Arabia – have also stoked tensions. Last week, Houthi rebels in Yemen aligned with Iran claimed responsibility for drone attacks on Saudi oil facilities.

Mr Bolton, along with Mr Pompeo, are perceived as Iran hawks within the Trump administration. Mr Bolton, one of the architects of the Iraq war during the presidency of George W Bush, has previously advocated regime change in Iran and suggested the US should bomb the country.

Nonetheless, Mr Trump has previously indicated he does not want to extend US involvement in the region, and instead pledged to withdraw American troops from Afghanistan and Syria.

“I don’t want to fight, but you do have situations like Iran, you can’t let them have nuclear weapons,” Mr Trump told Fox News over the weekend.