The report from state media KCNA on Tuesday came a day after US President Donald Trump said he might meet Kim during a planned trip to Asia.
Trump is expected to attend the Asia-Pacific Economic Co-operation summit in China in mid-November.
Kim, accompanied by his daughter known as Ju Ae and wife Ri Sol Ju, attended the opening of the newly opened Defence Revolution Museum on Sunday, KCNA said.
The museum displayed weaponry developed under Kim's leadership ranging from drones to the Hwasong-20 intercontinental ballistic missile (ICBM), KCNA photographs showed.
A display in front of the Hwasong-20 launcher appeared to show a multiple warhead design and a world map depicting ranges extending beyond the US mainland to the Middle East, Australia and South America, said Shin Jong-woo, Secretary General of the Korea Defence and Security Forum.
"The exhibition appears intended to highlight the achievements of Kim's defence science development program," Shin said.
"It gave the impression of propaganda aimed at gaining a strategic advantage ahead of potential a North Korea-US summit."
Analysts said the museum also reflected a broader effort by Kim to elevate North Korea's weapons displays into lasting symbols of the regime's military accomplishments.
"By turning what were once temporary weapons exhibitions into a permanent museum, Kim is institutionalising his military achievements and portraying North Korea's nuclear and missile buildup as a completed and enduring legacy," said Lim Eul-chul, a professor at Kyungnam University's Institute for Far Eastern Studies.
Separately, North Korea said it test-fired a tactical ballistic missile on Monday to confirm the successful technical upgrade of an unspecified key component.
KCNA said the upgrade marked an important step in improving the performance of all offensive weapons systems, without providing further details.
South Korea's military said on Monday that North Korea had fired multiple ballistic missiles towards the sea off its east coast. The launch was Pyongyang's fourth in a month, following Seoul's recent test of a hypersonic missile.
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