The influential sister of North Korean leader Kim Jong Un has been appointed to the country's top government body, the official KCNA news agency reported on Thursday.

Kim Yo Jong was promoted to a position on the State Affairs Commission (SAC), the country's top government body, the report confirmed. Analysts say her latest rise reinforces her position in Pyongyang's power circles.

It is a significant advancement from her relatively junior position as a vice department director in the ruling party, and it is sure to fuel speculation that she could be a long-shot candidate to succeed her brother, whose health is a constant source of speculation, in the event of his death.

The socially conservative North would get its first female leader as a result of such a change.

Yo Jong is now the most senior member of the "Paektu bloodline," a Northern term for the siblings' grandfather Kim Il Sung and his descendants, who have ruled the nuclear-armed country since its foundation.

Her promotion comes after the Supreme People's Assembly, the rubber-stamp parliament, approved a slew of changes.

Nine members of the commission were fired, including Pak Pong Ju, one of the panel's vice presidents, and diplomat Choe Son Hui, a rare senior woman in the North's hierarchy who played a crucial role in negotiations with the US.

On Thursday, the official Rodong Sinmun newspaper published photos of the eight new appointees, with Yo Jong standing out for her youth and as the only woman among them.

In statements aired by state media, she has made vehement denunciations of Washington and Seoul, particularly ahead of the North blowing up a liaison office on their side of the border that the South had built and paid for.

She recently sent a series of messages to Seoul in which she expressed her willingness to improve relations if the South Korean government changed its stance toward the North.

In a parliamentary session on Wednesday, Jong Un endorsed that message, saying that communications lines with the neighboring country, which had been shut off since August, will be reconnected in the coming days and urging Seoul to change its "attitude" to improve cross-border ties.

Yo Jong's official rank has risen and dropped over time, but her new SAC position is by far her most senior.