Seoul: The young daughter of North Korean leader Kim Jong-un, Ju-ae, appears to have bolstered her status as Kim's likely successor through her recent trip to China, South Korea's spy agency said Thursday.

According to Yonhap News Agency, Ju-ae, believed to be in her early teens, stayed inside the North Korean Embassy and avoided media exposure during her trip but managed to secure enough of the "narrative" necessary to solidify her position as a potential successor, lawmakers told reporters, citing the National Intelligence Service's (NIS) closed-door briefing.

The NIS also assessed that Kim has no major health problems, noting his heart rate and blood pressure remain within normal ranges.

North Korean state media showed Ju-ae accompanying Kim on his trip to Beijing last week to attend a military parade, further fueling speculation that she may be next in line for succession.