North Korean leader Kim Jong-un stayed out of public sight Saturday, as the reclusive nation's tightly controlled media focused their coverage on the founding anniversary of its armed forces.

They have carried no report of Kim's public activity since April 11, sparking speculation that the 36-year-old might be critically ill.

Pyongyang's propaganda outlets instead hyped the 88th anniversary of the birth of the Korean People's Revolutionary Army (KPRA) that falls on April 25.

The official Korean Central News Agency detailed the history of the KPRA that dates back to the anti-Japanese people's guerrilla army formed by Kim Il-sung, late grandfather of the current leader. Korea was under Japan's brutal colonial rule at that time.

In an editorial, the Rodong Sinmun, the organ of the North's ruling party, stressed Kim Jong-un's call for bolstering the military power and urged the further strengthening of the entire army's support for his leadership.

A South Korean Joint Chiefs of Staff officer said later in the day no unusual signs regarding the anniversary have been detected in North Korea.

Meanwhile, Reuters said China has dispatched a team of medical doctors and officials to North Korea "to advise on" Kim. It quoted three unnamed people familiar with the situation.

The delegation, led by a senior member of the Chinese Communist Party's International Liaison Department, left Beijing for North Korea on Thursday, it added. (Yonhap)