"The European measures have been insufficient … and the Islamic Republic will proceed with the second phase of reducing its commitments," said Iran's Foreign Minister Mohammad Javad Zarif July 1, after he officially confirmed that his country's stockpile of low-enriched uranium had exceeded 300 kilograms, a level set by the 2015 nuclear deal formally known as the Joint Comprehensive Plan of Action (JCPOA).

Zarif also announced that the same holds true for Iran's heavy water supplies, revealing that the reserve is already past the 130-ton limit, which Iran had been observing under the deal. The "second phase" Zarif warned about is the stage at which Tehran will push the scope of its uranium enrichment beyond 3.67%. That's one in a series of measures the Islamic Republic has decided to take against what it laments as European signatories' inaction in protecting the accord after US President Donald Trump unilaterally pulled his country out of it and triggered the resumption of secondary sanctions on Iran.

Zarif, however, added that Iran's moves are "revocable" if the Europeans fulfill their responsibilities. "If not — under Article 36 of the JCPOA — we reserve the right to implement our decisions, which are guarantees enshrined in the JCPOA."

As a July 7 deadline set by Iran for the European side looms large, the latter has been trying to finalize the implementation of the long-awaited Instrument in Support of Trade Exchanges (INSTEX), a channel meant to ease Iran's trade and help it sidestep US sanctions. Still, the launch of the mechanism has done little to appease the Iranians. "INSTEX was a preliminary step for Europe to honor 11 key commitments. They failed to honor them, and it [INSTEX] is being operationalized only after 14 months," Zarif said, noting that INSTEX will make no sense without those obligations, among them a return of Iran's oil revenues.