The state-run Korean Central News Agency reported the first details from the secretive party proceedings in Pyongyang.

Kim Jong Un was named first secretary of the Workers' Party. He is expected to have gained other new titles formalizing his position as ``supreme leader'' of North Korea's people, party and military at the fourth Workers' Party conference.

The young Kim, who was unveiled as father Kim Jong Il's choice as successor at a similar party conference in September 2010, assumed power following the longtime leader's December death.

His ascension to the party's top post comes during a week of events leading up to centennial celebrations marking the birth of his grandfather, North Korean founder Kim Il Sung. Kim Il Sung died in 1994 but remains the country's ``eternal president,'' just as Kim Jong Il was granted the general secretary title eternally on Wednesday.

Kim's 100th birthday is a major milestone in the nation he founded in 1948, and the streets were awash with new posters, banners and flags. Outside the city's war museum and the Pyongyang Indoor Stadium, women in traditional Korean dress gathered in clusters, practicing for special performances this week.

One of the main events planned for this week is a rocket launch poised to take place from a west coast launch pad as early as Thursday.

Space officials call the launch of the Unha-3 rocket, mounted with an Earth observation satellite, a ``gift'' to Kim Il Sung and aid the final step of injecting fuel into the three-stage rocket was under way.

A live feed from the General Command Center outside Pyongyang showed the rocket on the launch pad covered with a tarp to protect the satellite from the wind.

The United States, Japan, Britain and others see the planned launch as a provocation and violation of U.N. Security Council resolutions banning North Korea from developing its nuclear and missile programs.

In Pyongyang, party delegates shouted ``hurrah'' as the announcements were made about the Kims' titles, KCNA reported.

Delegates described Kim Jong Un as the ``heart'' of North Korea's military-first policy, KCNA said. (AP)