SEOUL - North Korean leader Kim Jong Un brought his teenage daughter to Beijing this week in her first public outing overseas, fuelling further speculation that she may be his potential successor in the family's dynastic rule over the nuclear-armed state.

Secretive North Korea has never revealed her name or age, but South Korean intelligence officials believe she is the daughter identified as Ju Ae by former American basketball player Dennis Rodman. Rodman spent time with Mr Kim’s family in 2013 and described holding her as a baby.

She was seen just behind her father as they stepped off the armoured train they used to travel overnight from Pyongyang to the Chinese capital Beijing, where Mr Kim Jong Un attended a massive military parade on Sept 3 staged by China to commemorate Japan's surrender ending World War II in the Pacific.

“Right now, Ju Ae is the front runner as next supreme leader of North Korea,” said Mr Michael Madden, a North Korea leadership expert at the US-based Stimson Centre. “She is getting practical protocol experience which should serve her well as North Korea’s next leader or a core elite.”

It is the first time she has accompanied Mr Kim outside North Korea – an experience that neither her father nor powerful aunt ever had, Mr Madden said.

“She is getting valuable experience greeting and interacting with foreign leadership and other elites,” he said.

Analysts said there is no evidence Mr Kim ever accompanied his father Kim Jong Il on overseas trips. The late Kim Jong Il did make foreign trips in the 1950s with his father, North Korea’s founder Kim Il Sung.

North Korea's tightly controlled state media had revealed nothing about Mr Kim Jong Un's children until Ju Ae was first shown to the world accompanying her father to the launch of a massive intercontinental ballistic missile in 2022.

There is still little known about other Kim children.

South Korea's intelligence agency considers Ju Ae to be the most likely successor so far, despite questions over whether she can ultimately rise to the top of the male-dominated dynasty.

Estimated to be about 13 years old, Ju Ae has attended increasingly high-profile events, including her diplomatic debut at a Russian Embassy event in May.

“The scope of her public appearances certainly has expanded from military-related sites to political and economic events over the years,” said Ms Rachel Minyoung Lee, another researcher with the Stimson Centre. “If this is part of a succession campaign, this would certainly help with that effort, as it would be seen as Kim Ju Ae’s debut on the international stage.”