The Democratic People's Republic of Korea revealed on Thursday that top leader Kim Jong-un's younger sister, Kim Yo-jong, holds the title of a senior party official, confirming her rise through the ranks as a potential key aide to the young leader.

Kim Yo-jong, believed to be 26, made her first public appearance during the funeral of then-leader Kim Jong-il in December 2011.

Since then, she has occasionally been seen accompanying her brother to political events and on his "field guidance trips", but without any specific title attached to her name.

That changed on Thursday when the DPRK's Korean Central News Agency listed her as a vice-director of a department of the central committee of the ruling Workers' Party of Korea.

She recently accompanied her brother on a trip to the Korean April 26 Cartoon Film Studio, which was founded on the instruction of then-leader Kim Il-sung in September 1957, KCNA said on Thursday.

During the visit, Kim Jong-un urged animators to produce works that are "true to the intention of the party".

It is not clear exactly what Kim Yo-jong's responsibilities are, but analysts suggested she was either in the powerful organizational department handling personnel changes or a propaganda unit.

Kim Yo-jong, the youngest in the family and said to have been born in 1987, studied at the prestigious Kim Il-sung University in Pyongyang and was tutored in English and French, according to Republic of Korea media.

DPRK watchers have speculated that Kim Yo-jong is being groomed to play the same leadership supporting role as her powerful aunt, Kim Kyong-hui.

Kim Kyong-hui, 68, was a close aide to her own brother and late leader Kim Jong-il for decades, assuming senior positions in the party and becoming a four-star general in 2010.

But she largely disappeared from public view after her husband, Jang Song-thaek, was executed in December on charges that included treason.

How powerful is she?

Yang Moo-jin, a Seoul-based professor specializing in the study of the DPRK, said it was still too early to say whether Kim Yo-jong will be able to acquire the same level of power and influence as her aunt.

"It's hard to gauge where she stands overall. Is she influential enough to communicate with top party officials? Or is she simply working at propaganda operations?" Yang said.

"It's hard to tell, especially with someone so young. So I think it's premature to say what role she is, or will be, playing," he added.

A resolution adopted at the UN earlier this month condemned alleged abuses of human rights in the DPRK, charges that Pyongyang has strongly rejected as politically motivated.

Mass rallies denouncing the adoption of the resolution have been held in cities across the DPRK in recent days.

Photos published in the WPK's central organ Rodong Sinmun on Thursday showed thousands marching with banners reading: "Let's become guns and bombs that protect the respected comrade Kim Jong-un!"

The largest rally was held in Pyongyang on Tuesday, with hundreds of thousands of troops and civilians packing the capital's Kim Il-sung Square.

AFP - Xinhua