BEIJING - Pyongyang formally declared Kim Jong-un "supreme leader", as the country staged a massive memorial service on Thursday for Kim Jong-il to end a period of official mourning.

Analysts said the new leadership of the Democratic People's Republic of Korea (DPRK) has to engage more with the international community to overcome challenges and maintain the stability of the Korean Peninsula.

A huge military memorial parade was held in Pyongyang on Thursday and tens of thousands of people were in attendance in the city's main square.

Kim Jong-un, head bowed and somber in a dark overcoat, stood on a balcony at the Grand People's Study House overlooking Kim Il-sung Square during the memorial.

Kim Yong-nam, a member of the Presidium of the Political Bureau of the Central Committee of the Workers' Party of Korea and president of the Presidium of the Supreme People's Assembly, delivered a memorial speech saying that Kim Jong-il devoted himself to "the accomplishment of the revolutionary cause of Juche, national reunification and global independence". Juche means self-reliance.

He declared Kim Jong-un "supreme leader" of the party, military and the people during the government's first public endorsement of his leadership.

Analysts said the ceremony is a formal declaration of national support for the young Kim.

What Kim Yong-nam said sent clear signals that the party, government and military have accepted the young Kim as the central figure of its collective leadership, Wang Junsheng, an expert on Asian studies at the Chinese Academy of Social Sciences, said.

Experts said the young leader needs a stable external environment for the implementation of smooth domestic and foreign policies.

Countries should give incentives for the DPRK's stability and development, instead of provoking the new leadership, Chen Qi, an expert on East Asia studies at Tsinghua University, said.