Radio Free Asia (RFA) says a U.S. envoy will visit North Korea again to get it to include the Japanese abductee issue in its nuclear declaration.

U.S. State Department official Sung Kim, the department's point man on Korean affairs, will be making the trip, his second in less than a month. Kim had visited Pyongyang in late April to discuss that country's declaration of its nuclear programs.

The broadcaster cited a diplomatic source in Washington as saying that U.S. nuclear envoy Christopher Hill has called on Pyongyang to take action on the abductee issue. Hill is said to have conveyed the U.S. stance to his North Korean counterpart Kim Kye-kwan when the two met last month in Singapore.

RFA went on to say that Sung Kim will link progress on abductees to North Korea's removal from a U.S. list of state terrorism sponsors. He'll tell his North Korean counterparts that such progress would allow confirmation of the schedule for the North's delisting.