The International Atomic Energy Agency had warned Saturday that the "disproportionate and unprecedented" move would seriously hamper its work.

Iranian media and a Western diplomat said the decision concerned eight inspectors, all from France and Germany.

Brussels, which acts as coordinator for the 2015 nuclear deal between Tehran and world powers known as the JCPOA, said it was "highly concerned" by the development.

"Particularly worrying is the direct and severe impact of this decision on the agency's ability to conduct its verification activities, which includes the monitoring of the Joint Comprehensive Plan of Action [JCPOA]," a spokesman said.

"The EU urges Iran to reconsider its decision without delay."

Iran's foreign ministry said Saturday that the move was in retaliation for "political abuses" by the United States, France, Germany and Britain.

In 2015, major world powers reached the accord with Iran under which Tehran would curb its nuclear programme in exchange for relief from crippling economic sanctions.

But that started to unravel in 2018 when Donald Trump, the US president at the time, withdrew from the deal and reimposed sanctions.

Tehran in turn stepped up its nuclear programme, while continuing to deny that it harbours ambitions of developing nuclear weapons capability.

Efforts to revive the deal have been fruitless so far.

Britain, France and Germany, European signatories to the deal, announced last week that they would not lift sanctions on Iran next month as originally foreseen.