Kim Dong-yub, a professor at the Institute for Far Eastern Studies, Kyungnam University in Seoul, said North Korea may have decided to release images of what appears to be a 3,000-ton submarine to appease an internal constituency, South Korean news service Newsis reported.
"The disclosure of the new submarine appears to be for domestic purposes that would not negatively affect U.S.-North Korea dialogue," Kim said.
On Tuesday, North Korea published photographs of Kim inspecting the newly constructed submersible craft.
"The Supreme Leader Comrade Kim Jong Un toured the newly constructed submarine," Pyongyang's state-controlled news agency KCNA said. "Under the careful guidance and special attention of the Supreme Leader, the submarine will carry out its mission in the East Sea."
South Korean analysts agree the new submarine is larger than the Sinpo-class submarine the North used to test-launch the Pukguksong-1 missile in August 2016.
The submarine deployed in 2016 was a 2,000-ton submersible craft with one launcher. The North Korean submarine unveiled on Tuesday appears to be capable of being equipped with as many as three launchers for submarine-launched ballistic missiles, or SLBMs.
North Korea's disclosure of the submarine comes at a time when the Trump administration continues to promote engagement with Pyongyang.
On Monday, U.S. Secretary of State Mike Pompeo told iHeartMedia that North Korea promised to denuclearize during the Trump-Kim summits.
Chairman Kim "promised that he would denuclearize his country. He did so publicly in a written document; he said so to President Trump. He has told me that half a dozen times personally," Pompeo said.
In the interview in Mexico City, Pompeo also said the United States needs North Korean negotiators to begin to "build out on those principles that the two leaders have set forward."
Trump most recently met with Kim at the Korean demilitarized zone in June.