North Korea has removed seals placed by the UN atomic watchdog on its nuclear facilities, South Korea's Yonhap news agency reported Monday.
The North said last week that it was working to restart its atomic reactor at Yongbyon and no longer wants US concessions promised under a landmark deal in return for its denuclearisation.
Yonhap gave no immediate details of the source of its information. US-based Fox News carried a similar report recently, although there has been no official confirmation.
The six-nation aid-for-disarmament deal is deadlocked by a dispute over verification of the nuclear declaration which the North delivered in June as part of the agreement.
The hardline communist regime stopped work to disable its Yongbyon complex last month before confirming last Friday that it was working to restart the plutonium-producing reactor.
North Korea is angry that the United States has failed to drop it from a terrorism blacklist in return for the disablement work.
Washington says it will not do so until it accepts outside inspections to verify the nuclear declaration.
