The United Nations Security Council will meet behind closed doors on Wednesday over Iran's expansion of its stock of uranium close to weapons grade, diplomats said on Monday.

The meeting was requested by six of the council's 15 members -- France, Greece, Panama, South Korea, Britain, and the U.S.

They also want the council to discuss Iran's obligation to provide the U.N. nuclear watchdog -- the International Atomic Energy Agency -- with "the information necessary to clarify outstanding issues related to undeclared nuclear material detected at multiple locations in Iran," diplomats said.

Iran's mission to the U.N. in New York did not immediately respond to a request for comment on the planned meeting.

Iran has denied wanting to develop a nuclear weapon. However, it is "dramatically" accelerating enrichment of uranium to up to 60% purity, close to the roughly 90% weapons-grade level, the IAEA has warned.

Western states say there is no need to enrich uranium to such a high level under any civilian program and that no other country has done so without producing nuclear bombs. Iran says its nuclear program is peaceful.

Iran reached a deal in 2015 with Britain, Germany, France, the U.S., Russia, and China -- known as the Joint Comprehensive Plan of Action -- that lifted sanctions on Tehran in return for restrictions on its nuclear program.

Washington quit the agreement in 2018 during Donald Trump's first term as U.S. president, and Iran began moving away from its nuclear-related commitments.

Britain, France and Germany have told the U.N. Security Council that they are ready -- if needed -- to trigger a so-called snap back of all international sanctions on Iran to prevent the country from acquiring a nuclear weapon.

They will lose the ability to take such action on October 18 next year when the 2015 U.N. resolution on the deal expires. Trump has directed his U.N. envoy to work with allies to snap back international sanctions and restrictions on Iran.