European participants in the 2015 nuclear agreement have expressed “grave concern” that Iran has stepped up its enrichment of 60% uranium.

The International Atomic Energy Agency reported earlier this week that Iran has started a second cascade to enrich the uranium, which is still short of the 90% grade required for a nuclear weapon.

On Thursday, the French, British, and German foreign ministries said in a joint statement, “We reiterate that these are serious violations of Iran’s commitments under the Joint Comprehensive Plan of Action….Iran must halt activities in violation of the JCPOA without delay.”

In April Iran began the 60% enrichment, in a further suspension of the terms of the deal, just after an explosion — believed to have been overseen by Israel — sabotaging the main nuclear complex at Natanz.

Amid the Vienna talks on a renewal of the deal, including US re-entry and lifting of American sanctions, Iran boasted of a sharp increase in 60% output in June, to 6.5 kg (14.3 lbs).

The Vienna talks adjourned in June. Iran’s lead negotiator, Deputy Foreign Minister Abbas Araqchi, said at the time that the discussion was “closer to the end of the road”.

But since then, Tehran has toughened its position amid the inauguration of the Raisi Government and the Supreme Leader’s denunciation of the “unjust and malicious” West. US officials says a resumption is unlikely before September.

See also Iran’s Supreme Leader Steps Back from Nuclear Negotiations

The European ministries said on Thursday:

Iran‘s activities are all the more troubling given the fact talks in Vienna have been interrupted upon Tehran’s request for two months now and that Iran has not yet committed to a date for their resumption. While refusing to negotiate, Iran is instead establishing facts on the ground which make a return to the JCPoA more complicated.