Nuclear officials have revealed that Iran quadrupled its uranium-enrichment production capacity amid tensions with the US over Tehran's atomic programme.

The announcement came after US president Donald Trump and Iran's foreign minister traded threats and taunts on Twitter.

Iranian officials stressed that the uranium would be enriched only to the 3.67% limit set under the 2015 nuclear deal with world powers – making it usable for a power plant, but far below what is needed for an atomic weapon.

Iran has quadrupled its ability to produce uranium meaning it could quickly exceed stockpile limits set under the nuclear deal, which it has threatened to tear up after US backed out (file)

Experts warned of Iran's nuclear capabilities as Trump hit out at the country's leadership on Twitter, amid fears of a conflict

However, by increasing production, Iran soon will exceed the stockpile limitations set by the accord.

Tehran has set a July 7 deadline for Europe to set new terms for the deal, or it will enrich closer to weapons-grade levels.

Spiralling tensions between the US and Iran has set the Middle East on edge, as Trump lashed out i a series of tweets described by Iran's foreign minister as 'genocidal.'

Already this month, officials in the United Arab Emirates alleged that four oil tankers were sabotaged.

Yemeni rebels allied with Iran launched a drone attack on an oil pipeline in Saudi Arabia, and US diplomats relayed a warning that commercial airlines could be misidentified by Iran and attacked, although this was dismissed by Tehran.

The President warned Iran never to threaten the US before revealing the country has not yet entered into negotiations, despite increased sanctions

On Sunday, a rocket landed near the US embassy in the Green Zone of Iraq's capital Baghdad, days after non-essential US staff were ordered to evacuate from diplomatic posts in the country. No-one was reported injured.

Iraqi military spokesman Brig Gen Yahya Rasoul told the Associated Press that the rocket was believed to have been fired from eastern Baghdad, an area home to Iran-backed Shia militias.

Iran's Foreign Minister Mohammad Javad Zarif called Trump's Twitter outbursts 'genocidal'

The Iranian enrichment announcement came after local journalists travelled to Natanz in central Iran, the country's underground enrichment facility.

The state-run IRNA news agency quoted Behrouz Kamalvandi, the spokesman of the Atomic Energy Organisation of Iran, as acknowledging that capacity had been quadrupled.

He said Iran took this step because the US had ended a programme allowing it to exchange enriched uranium to Russia for unprocessed yellowcake uranium, as well as ending the sale of heavy water to Oman. Heavy water helps cool reactors producing plutonium that can be used in nuclear weapons.

Mr Kamalvandi said Iran had informed the International Atomic Energy Agency of the development.

Tehran long has insisted it does not seek nuclear weapons, though the West fears its programme could allow it to build them.

Before Iran's announcement, Mr Trump tweeted: 'If Iran wants to fight, that will be the official end of Iran. Never threaten the United States again!'

An F/A-18E Super Hornet flies above the USS Abraham Lincoln in the Arabian Sea on Saturday

His remarks reflect what has been a strategy of alternating tough talk with more conciliatory statements he says is aimed at keeping Iran guessing at the administration's intentions. He also has said he hopes Iran calls him and engages in negotiations.

Iranian foreign minister Mohammad Javad Zarif soon responded by tweeting that Mr Trump had been 'goaded' into 'genocidal taunts'. Mr Zarif referenced both Alexander the Great and Genghis Khan as two historical leaders that Persia outlasted.

'Iranians have stood tall for a millennia while aggressors all gone,' he wrote. 'Try respect – it works!'

Mr Zarif also used the hashtag #NeverThreatenAnIranian, a reference to a comment he made during intense negotiations for the 2015 nuclear accord.