France, Germany, the UK, and the United States on Thursday condemned an increase by Iran in the production rate of highly enriched uranium of up to 60% purity, close to the level used for nuclear weapons fuel.

In a joint statement, the allies called for its reversal and said they remained “committed to a diplomatic solution” of the feud over Tehran’s nuclear program. Howver, they did not mention of any consequences Iran could face for the production hike.

“The production of high-enriched uranium by Iran has no credible civilian justification,” the statement said. “These decisions … represent reckless behavior in a tense regional context.”

Earlier on Tuesday, the UN nuclear watchdog, the International Atomic Energy Agency (IAEA), said in a report that Iran had reversed a months-long slowdown in the production rate of highly enriched uranium up to 60% purity.

Iran on Wednesday dismissed the IAEA report as “nothing new” and said it was running its program “according to the rules.”

Tehran already has enough uranium of 60% purity, if enriched to 90%, to make three nuclear bombs, according to the IAEA’s theoretical definition.