Kim Jong Un has been named first secretary of North Korea's ruling party, solidifying his position as heir to the political dynasty established by his father and grandfather.

The move late Wednesday comes shortly before the expected launch of what Pyongyang says is a weather satellite but has been denounced by other countries as a disguised ballistic missile test.

North Korea's official news agency says the youthful Kim, aged less than 30, was confirmed to the leadership post at a special conference of the Workers' Party of Korea. That marks a slight shift from the title held by his late father, Kim Jong Il, who had been declared the “eternal” general secretary of the party before his death in December.

The party conference and promised rocket launch are timed to mark the 100th anniversary of the birth of Kim Il Sung, the country's founding leader and father of Kim Jong Il.

Since his father's death, Kim Jong Un has moved quickly into a number of posts controlling the key levers of power in the secretive and authoritarian government.

A year before his father's death, he was made a four-star general, in spite of a lack of any military experience. In late December, he was named supreme commander of the military forces.

He has undertaken a number of guidance visits to military facilities and schools, usually accompanied by a group of men in their 70s and 80s.

It is believed he is being mentored by Kim Kyong Hui, an aunt who was close to Kim Jong Il, and her powerful husband, Jang Song Taek.