Iran has surpassed a limit on enriched uranium as outlined in the 2015 nuclear deal, international inspectors confirmed.

The 300 kg limit was outlined in the Obama-era nuclear agreement as a "sunset clause" that was meant to expire in 2030.

Iran initially stuck to this clause even after President Donald Trump pulled out of the deal last year.

European leaders unsuccessfully tried to persuade Iran not to breach the limits last Friday.

The stockpile, which is enriched to a relatively low level, can be used in power plants, but not to build nuclear weapons.

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Iran has surpassed its limit on enriched uranium stockpile as outlined in the 2015 nuclear deal, breaking a promise it was meant to keep until 2030.

The country's stockpile of uranium hexafluoride (UF6), enriched to 3.67%, surpassed 300kg as of Monday, a spokesman for the International Atomic Energy Agency (IAEA) told Business Insider in a statement.

The IAEA is the UN authority in charge of monitoring and verifying Iran's uranium stockpile. "Iran's total enriched uranium stockpile exceeded 300 kg of UF6 enriched up to 3.67% U-235," the IAEA spokesman said, citing the agency's chief.

Iran has committed to stay below 300kg until 2030, under the terms of the 2015 nuclear deal signed with the Obama White House and various other world powers.

The breach was first reported by Iran's semi-state-run Fars news agency on Monday.

Iranian Foreign Minister Javad Zarif also announced the breach on Monday, Reuters reported, citing Iran's ISNA news agency.

But Abbas Mousavi, a foreign ministry spokesman, said that the move is "reversible," according to Reuters.

A composite image of Iranian President Hassan Rouhani and President Donald Trump. Michael Gruber/Getty Images; Olivier Douliery-Pool/Getty Images; Samantha Lee/Business Insider

The 300 kg limit was outlined as a "sunset clause" — an agreement that will ultimately expire — in the 2015 nuclear deal, also known as the Joint Comprehensive Plan of Action (JCPOA). The limitation on uranium enrichment was meant to disappear in 2030.

Read more: Here's what's in the landmark nuclear deal that Iran is starting to walk away from amid tensions with Trump

Iran initially kept to its nuclear deal commitments even after President Donald Trump withdrew from the agreement last year.

However, after the US accused Iran of attacking two oil tankers in the Gulf of Oman last month, Tehran changed its mind and said on June 17 that it would breach the nuclear stockpile limit in ten days.

European leaders unsuccessfully tried to persuade Iran to drop its plan to breach the limits on Friday.

An oil tanker on fire in the Gulf of Oman on Thursday, June 13, 2019. AP Photo/ISNA

Breaching the limit is a symbolic defiance of Trump, but will not really put Iran much closer to building a nuclear weapon, The Washington Post's Loveday Morris noted.

Iran has repeatedly denied intentions to build a nuclear bomb.

The news comes after the US deployed its most advanced fighter jets, F-22 Raptors, to the Middle East amid increasing military tensions.

The 3.67%-enriched uranium can be used in power plants but nuclear bombs require more than 90% enriched uranium, Morris said.

However, a stockpile of 1,050 kg could be further enriched into enough material to build one nuclear bomb, the BBC reported, citing the Arms Control Association.

The US has already crippled Iran economically with sanctions. Last week Trump signed new sanctions specifically targeting the country's supreme leader.