SEOUL -- North Korean leader Kim Jong Un has promoted economic experts and his sister to key posts in the ruling Workers' Party of Korea, revamping the rogue state's diplomatic and economic leadership as the party celebrated its 72nd anniversary on Tuesday.

At a party meeting on Saturday, Kim stressed the need for a breakthrough that could transform the country into an independent economic power.

Tae Jong Su, an economic heavyweight and former vice premier, was made a member of the Politburo and a vice chairman of the Workers' Party. His promotion was intended both as a response to international sanctions and as preparation for bolstering the North's economy once it completes its nuclear weapons development, according to the Seoul-based Institute for National Security Strategy.

Foreign Minister Ri Yong Ho, who once suggested Pyongyang could test a hydrogen bomb in the Pacific Ocean, was promoted to the Politburo as well. It is believed to be rare for multiple foreign policy experts to occupy the body, which currently includes his predecessor Ri Su Yong. Kim may be trying to strengthen North Korea's diplomacy given growing pressure from the U.S. and China.

Kim's younger sister, Kim Yo Jong, was also given a seat in the Politburo. Believed to be only around 30 years old, she has nevertheless rapidly ascended the ranks. She was promoted to the Central Committee of the Workers' Party in May 2016.

Choe Ryong Hae, a vice chair of the party, was also made a member of the Central Military Commission in a signal of his rising influence.

With the reshuffle, Kim has replaced 26% of Politburo members, 44% of party vice chairs and 36% of the military commission, according to Cheong Seong-chang, a research fellow at the South's Sejong Institute.

South Korea's Ministry of Unification said Kim recognizes the severity of the current situation, and is hoping to both end his country's isolation by promoting diplomatic and economic experts, as well as usher in a new generation of leaders.

Nuclear weapons are a "guarantee" of victory over the U.S., the Workers' Party official newspaper, Rodong Sinmun, said in a Tuesday piece, stressing that Pyongyang was committed to perfecting its nuclear capability.

U.S. President Donald Trump also ramped up his rhetoric in a tweet Monday, saying the U.S. "has been unsuccessfully dealing with North Korea for 25 years."

North Korea did not make any military provocations on Tuesday, but Seoul expects Pyongyang to continue testing its intercontinental missiles and nuclear weapons. Given the rising tensions between the North and China, it could conduct some kind of demonstration when China kicks off its twice-in-a-decade Communist Party congress on Oct. 18.