Kim Yo Jong's profile has been rising since 2014, when she was made deputy director of the Propaganda and Agitation Department of the Workers' Party. She and Kim Jong Un were born to the same mother, Ko Yong Hui.
Kim Yo Jong was selected as an alternate member of the Political Bureau of the Central Committee of the Worker's Party at the Second Plenum of the party's 7th Central Committee.
Also in the reshuffle, according to state news agency KCNA, North Korean Foreign Minister Ri Yong Ho was selected as a member of the Politburo and Choe Ryong Hae, vice chairman of the Worker's Party and a close aide to Kim Jong Un, was appointed to the party's Central Military Commission.
Duyeon Kim, an analyst at the Korean Peninsula Future Forum, told CNN Kim's promotion of his sister "shows that he trusts her and that she is absolutely loyal to her brother."
"The whole slate of appointments and promotions he has made during the past meeting also shows that Kim Jong Un is trying to turn the Workers' Party into his party, into a Kim Jong Un party by filling senior positions and key positions with his people," she added.
Shadowy figure
The Politburo is the North Korean regime's top decision-making body, led by Kim Jong Un.
Born in 1987, Kim Yo Jong studied in Switzerland like her brother and is believed to have attended Kim Il Sung University and a western European school for her higher education.
"Since her brother's accession to the supreme leadership of (North Korea), Kim Yo Jong has been routinely observed attending Kim Jong Un's public appearances," NK Leadership Watch said.
Duyeon Kim said the continued promotion of his sister showed North Korea's leader was "trying to extend power and run the regime like a family dynasty, just like his father, just like his grandfather."
Nukes a 'powerful deterrent'
The key meeting of the Worker's Party comes amid an ongoing standoff between North Korea and the United States.
On Sunday, US President Donald Trump was critical of past attempts to reign in North Korea's missile and nuclear programs.
In a speech Saturday, Kim Jong Un said the country's nuclear weapons "are a precious fruition borne by its people's bloody struggle for defending the destiny and sovereignty of the country from the protracted nuclear threats of the US imperialists."
North Korea has long defended its nuclear program as essential to defend the country against US aggression, pointing to the experience of countries like Iraq and Libya.
Nuclear weapons, Kim said, are a "powerful deterrent firmly safeguarding the peace and security in the Korean peninsula and Northeast Asia and reliably guaranteeing the Korean nation's sovereignty."
October 10 marks the founding anniversary of the Worker's Party. North Korea has in the past marked key dates with missile or nuclear tests.
According to KCNA, Kim "noted with appreciation that the country's science and technology have developed by leaps and bounds and the national economy has grown on their strength this year, despite the escalating sanctions of the US imperialists and their vassal forces."
CNN's Will Ripley and Dugald McConnell contributed reporting.









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