Yet an official end to the Korean War and a deal on denuclearization haven't been this tantalizingly close in decades.
The apparent divergence of views between the US allies come ahead of a planned summit between Kim and US President Donald Trump on Jun 12 in Singapore to discuss ending the North's nuclear weapons program.
Kim's motivation remains unclear but analysts said the shake-up allows him and the ruling party to tighten control over the Korean People's Army (KPA) at a critical time of worldwide engagement and domestic development.
"This reshuffle has brought to the fore the officers who can do just that".
The North, meanwhile, has noted possible stumbling blocks for the talks, including denunciations of upcoming military exercises involving the United States and South Korea.More news: Nadal thumps Gasquet at Roland Garros
These words echo the statement of the US Secretary of State Mike Pompeo, who said in May that Washington plans to allow private investments and provide "sanctions relief" if the North Korean government dismantles its nuclear arsenal.
Japanese Prime Minister Shinzo Abe has reiterated in recent years, back when North Korea was still ratcheting up tensions, that maintaining "pressure" on Pyongyang is vital to compel it to discard its nuclear weapons and ballistic missiles.
Yonhap identified the three officials as defence chief Pak Yong-sik, chief of the Korean People's Army's (KPA) general staff Ri Myong-su, and director of the KPA's General Political Bureau Kim Jong-gak.
The White House, State Department, CIA and Office of the Director of National Intelligence did not respond immediately to requests for official comment.
"I am going to visit the DPRK and meet HE Kim Jong-un", Assad was quoted saying in the report, using the initials for North Korea's official name and referring to Kim using letters that stand for "his excellency".More news: New Italian govt vows to create jobs, deport migrants
The moves are likely linked in part to Kim Jong Un's drive to have the military take a bigger role in critical infrastructure projects.
"Kim Jong Un has chosen a new leadership who reflects his new approach and can more naturally propagate his new policies to bring stability within the military", the professor said.
Kim Jong Un is also likely expecting to receive more worldwide economic aid and investment soon as part of the ongoing talks and he wants to prevent corruption that plagued some past projects, Madden said.
Citing an unnamed intelligence official, Yonhap said No Kwang-chol, first vice minister of the Ministry of People's Armed Forces, had replaced Pak Yong-sik as defence chief, while Ri Myong-su was replaced by his deputy, Ri Yong-gil. "North Korea will receive relief only when it demonstrates verifiable and irreversible steps to denuclearization", Mattis added.
Abe said at a joint press conference with Trump on April 18 in Palm Beach, Florida, that they "completely" agreed to keep maximum pressure on Pyongyang, more than one month after the U.S. President chose to hold a summit with North Korean leader Kim Jong Un. "All three of them have held very sensitive and high level positions under Kim Jong Un, they're very loyal (to him), and all have experience interacting with foreign delegations".More news: Under Growing International Pressure, Maduro Releases More Venezuelan Political Prisoners