"We, the governments of France, Germany and the United Kingdom, condemn Iran's latest steps... to expand its nuclear programme," the three countries said in a joint statement.

Iran has revamped an enrichment plant at Fordo, south of Tehran, according to an International Atomic Energy Agency (IAEA) report seen by AFP.

The changes would "significantly increase the rate of production of uranium enriched up to 60 percent", the IAEA said -- on its way to the 90 percent needed to make a nuclear weapon.

Berlin, London and Paris, who along with the United States have held talks with Iran said they "strongly urge Iran to reverse these steps, and to immediately halt its nuclear escalation".

They recalled that their diplomats had met the Iranians in Geneva last week to discuss the country's nuclear programme "and reiterated their commitment to dialogue and constructive behaviour".

Iran insists on its right to nuclear energy for peaceful purposes and has consistently denied any ambition of developing weapons capability.

But according to the IAEA, it is the only non-nuclear-weapon state enriching uranium to 60 percent purity.

IAEA chief Rafael Grossi told AFP last week that Iran's expansion of enrichment was "a clear message that they are responding to what they feel is pressure".

Iran said last month that it would launch "new and advanced" centrifuges in response to an IAEA resolution that censured Tehran for what the agency called lack of cooperation.

Tehran has twice been censured at the IAEA's 35-nation board this year, with the latest motion brought by Britain, France, Germany and America.

Its "actions have further hollowed out the JCPoA (nuclear deal)," the European governments said Tuesday.

Nuclear tensions between Iran and the West have simmered since Donald Trump during his first term as US president tore up a landmark 2015 deal with Tehran that exchanged sanctions relief for limits on its nuclear programme.