The UN’s atomic watchdog says its inspectors have confirmed that Iran has started enriching uranium up to 20% purity, a technical step away from weapons-grade levels.

It is the latest in a string of violations of the 2015 nuclear deal with world powers.

The International Atomic Energy Agency reported in a confidential document distributed to member countries, and seen by the Associated Press, that as of February 16 Iran had added 17.6kg (38.8lb) of uranium enriched to 20% to its stockpile.

Overall, it increased its stockpile of enriched uranium to 2,967.8kg (6,542.9lb), up from 2,442.9kg (5,385.7lb) reported on November 2.

The nuclear deal signed in 2015 with the US, Germany, France, Britain, China and Russia, known as the Joint Comprehensive Plan of Action, or JCPOA, allows Iran only to keep a stockpile of 202.8kg (447lb).

It also allows enrichment only up to 3.67%.