Abbas Araghchi
Abbas Araghchi Reuters

Iran on Sunday will officially announce an increase in uranium enrichment to 5%, a concentration above the limit set by its 2015 nuclear deal, an Iranian official told Reuters on Saturday.

"The main announcement tomorrow will be the increase of the level of enrichment to 5% percent from 3.67% that we agreed under the deal," the official said on condition of anonymity.

Iran's semi-official Fars news agency reported that senior nuclear negotiator Abbas Araqchi would announce more cuts in its commitments to the pact at a news conference at 10:30 a.m. (0600 GMT) in Tehran.

The planned announcement follows Iranian President Hassan Rouhani’s declaration this past week that Iran would begin breaking another key limit set by its 2015 nuclear deal with world powers.

Tensions have been on the rise between Iran and Western powers since US President Donald Trump withdrew from the nuclear deal last year and then imposed a series of crippling sanctions on Iran’s economy.

Iran has threatened to abandon further nuclear commitments unless the deal's remaining partners -- Britain, China, France, Germany and Russia -- helped it circumvent US sanctions, especially to sell its oil.

Last Friday, Iran met in Vienna with European, Russian and Chinese officials to discuss ways to save the 2015 nuclear following the US withdrawal.

Iran’s envoy to the meeting in Vienna said that European countries had offered too little to persuade Tehran to back off from its plans to breach limits imposed by the deal.

The EU earlier this year introduced a trade mechanism that would bypass US sanctions on Iran, in a bid to save the 2015 deal, but Iran has rejected that mechanism thus far.