TEHRAN, Iran — Iran's president is warning Europe that Tehran will "take the next step" in increasing its uranium enrichment this coming Sunday.

The comments Wednesday by President Hassan Rouhani further increases pressure on European partners to salvage the unraveling 2015 nuclear deal following the U.S. withdrawal from the accord last year.

Rouhani says: "If you want to express regret and issue a statement, you can do it now."

President Donald Trump pulled America from Iran's nuclear deal last year and restored crippling economic sanctions.

Iran this week breached a low-enriched uranium stockpile limitation set by the deal and said by Sunday it would increase its enrichment of uranium closer to weapons-grade levels if Europe does not offer it a new deal.

Inspectors for the International Atomic Energy Agency, the U.N. nuclear watchdog, confirmed this week that Iran had accumulated more enriched uranium than allowed under the previous deal.

The agency said it had verified that Iran's total enriched uranium stockpile had exceeded 300 kg (661 pounds) of uranium enriched up to 3.67 percent U-235 "or the equivalent in different chemical forms" — the limit set by the nuclear deal.

Enriched uranium is used in energy production, although stockpiling uranium is also a necessary step to building nuclear weapons, which Iran has denied doing.