North Korean leader Kim Jong Un has returned from a monthlong break from public view to inspect a major development project near the border with China, which he said epitomizes his country’s “iron will” to achieve prosperity in the face of international isolation and pressure.

The North’s official Korean Central News Agency said Tuesday that Kim expressed satisfaction during his visit to Samjiyon city over the progress of construction in an area he called the “sacred place of the sun.” Samjiyon is at the foot of Mount Paektu, the heart of North Korea’s foundation myth revolving around the Kim family and is described by official narratives as the spiritual center of the country's revolution.

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Building Samjiyon into a “model cultured city” was one of the main focuses of a nationwide construction campaign that North Korea had aimed to complete in time for the 75th anniversary of its ruling party’s founding in October last year. But construction was slowed amid pandemic border closures and international sanctions over Kim’s nuclear weapon and missile programs.

Kim has been struggling to overcome what appears to be his toughest period as leader with the country's self-imposed COVID-19 lockdown creating a further shock for an economy battered by sanctions and decades of mismanagement.

KCNA said the construction at Samjiyon could be finished by the end of this year, which could give Kim a badly needed trophy achievement as he reaches a decade in rule since taking power following the death of his father in December 2011.

Kim praised workers for their “lofty loyalty, strong will and sweat” to push ahead with the project in the face of an “unfavorable environment” and said Samjiyon would become a guideline for rural development. He said the four years the country has spent developing Samjiyon, which involved the building of thousands of houses and buildings as well as new roads and a power grid, demonstrated its single-minded unity and “iron will” to “achieve prosperity our own way,” KCNA said.

The visit was Kim’s first public appearance reported in state media since he delivered a speech at an arms exhibition on Oct. 11.

“Claiming the success of Samjiyon’s development is politically important at this time because the Mount Paekdu region is central to North Korean mythology and the embellished story of the previous leader‘s birth,” as Kim may soon commemorate 10 years since his father’s death, said Leif-Eric Easley, a professor at Ewha University in Seoul.

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North Korea closely associates Paektu with Kim’s state-founding grandfather, Kim Il Sung, who, according to official narratives, saved the Korean Peninsula with daring guerrilla raids against Japanese invaders from his base on the mountain’s slopes before the end of World War II. North Korea also claims, probably incorrectly, that Kim Jong Un’s father, Kim Jong Il, was born on Paektu.

Since becoming leader, Kim Jong Un has spent years consolidating his power by removing political rivals and family members while spurring the development of nuclear weapons and missiles he sees as his strongest guarantee of survival.

He initiated diplomacy with former U.S. President Donald Trump in 2018 while attempting to leverage his nuclear program for sanctions relief, but those talks derailed in 2019 because of disagreements over a proposed withdrawal of U.S.-led sanctions in exchange for partial denuclearization by North Korea.