The invitation was made in a meeting in Pyongyang between Zhou Yongkang, the ruling Communist Party’s ninth-ranking leader, and the North’s supreme leader Kim Jong Il, the official Xinhua news agency reported.

It follows the elevation of Kim’s youngest son, Kim Jong Un, as heir apparent. He made his public debut late last month at the biggest North Korean Workers’ Party gathering in 30 years when he was promoted to vice chairman of the ruling Workers’ Party of Korea’s central military commission, which oversees the country’s active nuclear and missile programs. He was made a four-star general the day before the meeting.

Xinhua said Zhou invited the senior Kim and "the new DPRK leadership to visit China at a convenient time," referring to the reclusive country by its formal title, the Democratic People’s Republic of Korea.

Xinhua said that Kim told Zhou that the leaders of the Workers’ Party of Korea wanted to educate the "younger generation about the traditional friendship between the two countries … and sincerely learn about China’s experience."

China is impoverished North Korea’s closest ally. China’s economy has taken off in the last three decades through market reforms while North Korea’s hardline socialist system has stagnated and the country has been forced to turn to China and international aid groups for help to feed its population.

North Korea’s succession is closely watched because of concerns over 68-year-old Kim Jong Il’s health and the possibility of instability in North Korea if its leader were to die without a firm succession plan.

China, which is thought to have influence over North Korea as its biggest diplomatic ally and source of assistance, hasn’t officially commented on the succession process.