Iran admitted on Monday that it has passed the 300 kilos threshold of low-enriched uranium stockpile allowed under the 2015 nuclear deal.

The statement was confirmed by the International Atomic Energy Agency and the United Nations’ nuclear watchdog. The uranium stockpile enriched to 3,67% is suitable for nuclear power fuel but is far short of weapons-grade level, which requires fissile material enriched by 90%. The effect of this development is largely symbolic.

However, this is the first step of escalation. The second is expected on July 7, when Iranian officials have warned the will begin the process of weapon’s grade enrichment. In the past, Iran has warned would move to 20% enrichment, still below weapons-grade, far above the fossil fuel requirements, but one step closer to a nuclear weapon.

Iranian Foreign Minister Mohammad Javad Zarif said the move was “reversible” but warned Tehran’s European allies that it was time for them to step up to uphold the other side of the deal, the Islamic Republic News Agency (IRNA) reports.

Following the US unilateral withdrawal from the nuclear deal in 2018, Germany, Britain and France have designed, developed, and eventually launched a complex barter system that would continue to allow European businesses to trade with Iran. Thus far, the vehicle is limited in scope, focusing on essential goods such as medicine and food, which are not hit by US sanctions.  Moreover, a transaction has yet to be completed through the barter system.

When the US withdrew from the agreement, EU signatories undertook 11 commitments to keep the deal alive, which included continuing to buy Iranian oil, return frozen Iranian assets. Brussels has failed to deliver on these commitments, Zarif recalled on Monday.

Last week, US Special Envoy for Iran Brian Hook reiterated Washington’s commitment to secondary sanctions, targeting any country that dares to buy Iranian oil.

If Iran moves toward a full breach of the deal on July 7, then barter transactions may become impossible.