North Korean leader Kim Jong-un caught the eye of international observers on Sunday during a speech marking the anniversary of the ruling party's founding, but not because of his words, but because of his choice of footwear.

Kim walked the red carpet in the opulent hall in glittering black sandals over black socks to complement her dark suit, burgundy tie and half-frame glasses, according to footage released by state media on Monday.

Colin Zvirko, a senior analyst for Seoul-based NK News, noticed Kim's shoes and said it was unclear why Kim had decided to wear sandals and whether he had worn them before.

"For whatever reason, Kim seems to be taking steps lately to protect her health and comfort," he said.

- He lost a significant number of pounds in a short period of time in May, and in September he was seen standing on mats during long speeches, which is not usual. "He seems to be particularly wary of covid-19 and may be facing ongoing health problems," Zvirko said.

Kim's clothing choices are often scrutinized by international analysts, who look for signs of his health, which is a closely guarded secret in North Korea.

When Kim reappeared in the state media in early June after not appearing in public for almost a month, analysts noted that his watch was tighter than usual attached to a seemingly thin wrist, and raised rumors about the health of a leader who firmly rules North Korea.

The state media later mentioned the leader's health, which they rarely do. They quoted an unidentified Pyongyang resident as saying that everyone in North Korea was broken when they saw the photos of Kim looking "weak".