Iran has reportedly exceeded the uranium enrichment limit under the 2015 nuclear deal, according to the International Atomic Energy Agency on Monday.

The maximum of low-enriched uranium, 660 pounds, is not enough to produce a nuclear bomb. But exceeding it is a sign of Iran appearing to disregard the 2015 accord, which the United States withdrew from in May 2018, in addition to reimposing sanctions lifted under it alongside enacting new penalties against Tehran.

“We can confirm that IAEA Director General Yukiya Amano has informed the Board of Governors that the agency verified on July 1 that Iran’s total enriched uranium stockpile exceeded [660 Ibs.] of UF6 [uranium hexafluoride] enriched up to 3.67 percent U-235 (or the equivalent in different chemical forms),” an IAEA spokesperson told the BBC.

Recently, Iran quadrupled its production of low-enriched uranium, according to nuclear officials.

“Based on what I have been told, Iran has exceeded the limit in accordance with its plan,” Iranian Foreign Minister Mohammad Javad Zarif told reporters, according to Isna news agency.

“We have clearly said what we will do, and we will act accordingly. We deem it as part of our rights under the Joint Comprehensive Plan of Action,” he added, referring to the official name of the 2015 agreement, abbreviated as JCPOA.

Iran had given the European powers involved in the 2015 accord—the United Kingdom, France and Germany—a 60-day ultimatum to renegotiate the pact, however, it appears that they were unable to compensate for the effects of U.S. sanctions.