Asked whether Russia was assisting North Korea's nuclear development, IAEA chief Rafael Grossi said the agency had not seen "anything in particular in that regard". SEOUL: North Korea is showing a "very serious increase" in its ability to produce atomic weapons, the head of the United Nations' nuclear watchdog said Wednesday (Apr 15) on a visit to Seoul. The diplomatically isolated north is believed to operate multiple facilities for enriching uranium, a key step in making nuclear warheads,