North Korean leader Kim Jong Un is known for executing high-level officials, killing roughly 70 since December 2011. Above, Kim, second from left, smiles during a visit to a newly built building of the Automation Institute of the Kim Chaek University of Technology in Pyongyang, in this undated picture released by North Korea's Korean Central News Agency, July 3, 2015. Reuters

North Korea's senior leadership looks very different than it did five years ago. Under Kim Jong Un, numerous party and military leaders have been culled, with 20 percent to 30 percent of senior party officials replaced and more than 40 percent of senior military officers gone, according to North Korea's National Intelligence Service, Chosun Media reported Tuesday.

It was not immediately clear exactly what replacement meant, but some 70 North Korean officials, including a former minister, have been executed since the beginning of 2015, the National Intelligence Service said. The vast reshuffling of the party and military leadership has been ongoing since since Kim came to power in 2011.

The 32-year-old leader has enacted what South Korean officials have described as a "reign of terror." Kim's predecessor and father, Kim Jong Il, was also known for carrying out terrifying purges and arrests. He executed about 10 people in the early years of his reign, but Kim Jong Un has quickly outstripped that, doing away with high-level officials for reasons that reportedly range from personal disloyalty to national treason, USA Today reported earlier this month.

In December 2013, Kim executed his uncle, Jang Song Thaek, who at one point was the second-most powerful man in North Korea. Rumors circulated that all of Jang's immediate family were also killed. In May, Hyon Yong Chol, the defense minister, reportedly was executed by firing squad before hundreds at a military school in the capital, Pyongyang.

Of the dozens of officials executed in North Korea, many have been killed by machine-gun fire, the South Korean government has said. The changes in leadership could be an effort by Kim to consolidate control of the government and diminish the power of the military. Independently verifying reports from the secretive and enigmatic nation is extremely difficult, if not impossible.

The National Intelligence Service's briefing to lawmakers reportedly included information about the luxury brands Kim and his wife, Ri Sol Ju, prefer, such as Movado watches. The government also is preparing to spend vast amounts on anniversary celebrations for the Korean Workers' Party, including on a giant float on the Taedong River, fountain laser shows and a military parade, Chosun reported.