SEOUL, South Korea — It read like typical North Korean propaganda: soldiers toiling on snowy hills near the border with China, racing to finish construction on a tourist resort and making great sacrifices for the glory of the state.

But the report in March in a North Korean state newspaper also revealed the economic dysfunction under Kim Jong-un, the North Korean leader. Workers building up the city of Samjiyon, one of Mr. Kim’s marquee projects, were “breaking the frozen ground with hammers and chisels and carrying earth with stretchers and gunny sacks,” the report said.

The report, in the newspaper Rodong Sinmun, the mouthpiece of the government, followed South Korean media reports of cases of pneumonia and frostbite in Samjiyon. Together they suggest that American-led sanctions over North Korea’s nuclear weapons program are hurting Mr. Kim in a way they haven’t before: by targeting the state-run economy and the party and military elite who support his totalitarian rule.