VIENNA (AP) — The United Nations' atomic watchdog agency says Iran has continued to increase its stockpiles of enriched uranium and remains in violation of its deal with world powers.

The International Atomic Energy Agency reported the finding Friday in a confidential document distributed to member countries and seen by The Associated Press.

The agency said that as of May 20, Iran’s total stockpile of low-enriched uranium amounted to 1,571.6 kilograms (1.73 tons), up from 1,020.9 kilograms (1.1 tons) on Feb. 19.

Iran signed the nuclear deal in 2015 with the United States, Germany, France, Britain, China and Russia. Known as the Joint Comprehensive Plan of Action, or JCPOA, it allows Iran only to keep a stockpile of 202.8 kilograms (447 pounds).

The U.S. pulled out of the deal unilaterally in 2018.