North Korean leader Kim Jong Un (center) applauds during a photo session with the soldier-builders who performed labor feats in building the Wonsan Baby Home and Orphanage in this undated photo released by North Korea's Korean Central News Agency in Pyongyang, June 3, 2015. The leader's sister has apparently taken over the country's Propaganda Department. Reuters

North Korean leader Kim Jong Un reportedly now relies on his younger sister to steer his party's propaganda department, according to a report Wednesday from South Korea's Yonhap News. Kim Yo Jong, the leader's 28-year-old sister, took over the position after a department shakeup.

North Korea announced in November 2014 that Kim Yo Jong had taken on the title of deputy director of North Korea's ruling Workers' Party of Korea -- a job that had unclear duties, Yonhap reported. Officials told the news service that Yo Jong has since ascended to the top of the Propaganda Department. "It has not been confirmed what Kim's specific are, but given the nature of the leader's field guidances with her accompanying, she could be in charge of propaganda work," said a government official.

Kim Ki-nam, the person formerly in charge of North Korea's Propaganda Department, has not been seen publicly since April, which led to rumors of his retirement. Last year, Kim Jong Un reportedly got rid of three different leaders in the Propaganda Department. It now appears the Kim's sister has filled that void.

The move strengthens the leader's tight grip on North Korea. In recent months, he has reportedly begun replacing veteran military leaders with people nearer his age to overhaul the military to his liking. He's also removed or executed most anyone who challenged his power. An estimated 70 leaders and about 400 lower officials have reportedly been executed this year under Kim, according to the Cato Institute, a right-leaning U.S. think tank.

Kim Jo Yong -- following rumors of pregnancy -- made her first public appearance in 47 days toward the end of May, UPI reported. Her recent reappearance coincided with the timing of the rumored birth. Kim Jo Yong made the appearance in a video stream, alongside Kim Jon Un and his entourage, during a tour of the construction at a tree nursery.