Choe Son-Hui, who formerly served as North Korea's vice foreign minister, was tapped to lead the foreign ministry at a ruling party meeting overseen by the leader Kim Jong UN, the state media KCNA reported.
Veteran diplomat Choe Son-Hui is its first female foreign minister as Pyongyang pushes ahead with a blitz of sanctions-busting weapons tests and ignores the US calls for talks.
She replaces Ri Son Gwon, a hardline former military official who previously led talks with the South.
The appointment comes as the United States warned this month that North Korea is preparing to conduct a seventh nuclear test, and says it will again push for United Nations sanctions if that happens.
Kim vowed on Friday that he would use "power for power" to fight threats to the country's sovereignty, but did not mention a nuclear test and offered no details about how he would bolster military power.
"The right to self-defense is an issue of defending the sovereignty, clarifying once again the Party's invariable fighting the principle of power for power and head-on contest," state agency KCNA quoted Kim as saying in a meeting of the Central Committee of the Workers' Party of Korea.
Choe played a key role during North Korea's summits with the US, leading an aggressive negotiation effort aimed at the US leadership of former President Donald Trump. Her statements published on North Korean state media alternated between threatening a "nuclear showdown" to offers of dialogue.
She accompanied North Korean leader Kim for summits in Singapore in 2018 and Hanoi a year later, sitting alongside him at the negotiation table. In her latest statement in March of last year, she demanded the US cease its "hostile policy" against North Korea, including its joint drills with South Korea.
Experts offer different explanations of Choe’s promotion and what it means for diplomacy with Pyongyang.