South Korea's spy agency says North Korean leader Kim Jong Un has ordered the execution of 15 senior officials this year who were accused of challenging his authority.

Lawmaker Shin Kyoung Min said National Intelligence Service chief Lee Byoung Ho also told legislators in a closed-door briefing Wednesday that Kim appeared likely to visit Russia next month to attend the 70th anniversary of its victory over Nazi Germany in World War II.

The intelligence agency declined to confirm the information when contacted by The Associated Press.

The South Korean spy agency has a spotty record of tracking developments in North Korea. Information trickling out of the highly secretive state is often difficult to confirm.