TOKYO, Dhu-AlQa'dah 14, 1437, Aug 17, 2016, SPA -- North Korea says it has resumed plutonium production by reprocessing spent fuel rods and has no plans to stop nuclear tests as long as perceived U.S. threats remain, Japan's Kyodo news agency reported on Wednesday, Reuters reported. North Korea's Atomic Energy Institute, which has jurisdiction over the country's Yongbyon nuclear facilities, also told Kyodo it had been producing highly enriched uranium necessary for nuclear arms and power "as scheduled." "We have reprocessed spent nuclear fuel rods removed from a graphite-moderated reactor," the institute told Kyodo in a written interview. The institute did not disclose the amount of plutonium or enriched uranium it had produced, Kyodo said, but it has been understood for months that North Korea has resumed plutonium production at the site. In June, the U.N. nuclear watchdog, the International Atomic Energy Agency, said North Korea appeared to have reopened the Yongbyon plant to produce plutonium from spent fuel, and a senior official of the U.S. State Department said North Korea had restarted production of element. On Wednesday, the U.S. State Department said it was aware of the reported North Korean comments and called such activities "a clear violation" of U.N. resolutions. "We call on North Korea to refrain from actions and rhetoric that further raise tensions in the region," said Katina Adams, a spokeswoman for the department. North Korea vowed in 2013 to restart all nuclear facilities, including the main reactor at Yongbyon, which had been shut down. It said last September that Yongbyon was operating and that it was working to improve the "quality and quantity" of its nuclear weapons. North Korea conducted its fourth nuclear test in January and tested a long-range rocket the following month, prompting a new round of international sanctions. -- SPA 23:02 LOCAL TIME 20:02 GMT www.spa.gov.sa/w