The state-run North Korean media have, for the first time ever, broadcast footage of a speech by Kim Yo-jong, the influential sister of the North Korean leader.

The Korean Central News Agency aired a recording on Thursday of a speech that was made the day before at a national meeting during which Kim Jong-un's sister shared an anecdote about the leader suffering from a "high-fever" during the pandemic, bringing some audience members to tears.

She glorified her brother's leadership as she declared victory over COVID-19 and railed against South Korea with claims that it was responsible for the outbreak in the North.

Some observers in the South assessed her vocal delivery to be somewhat shaky, which was perceived to be a reflection of her lack of experience in delivering an official address to such an audience, but the same assessments noted that she spoke in a calm manner.

When she blamed South Korea for the outbreak and vowed retaliation, her voice gained strength and became higher in tone but she still maintained a calm manner compared to the more aggressive delivery that commonly accompanies any talk of the South by the regime.