North Korea's army chief, second-in-command after Kim and principal advisor to the North Korean leadership, Ri Yong-ho, has been removed from all official posts because of illness, said Pyongyang's state media on Monday.

Ri's ouster has sparked widespread speculation over the course of political action transpiring in the reclusive Asian nation.

On Sunday, the politburo of the Central Committee of the Workers' Party of Korea made the decision to relieve Vice Marshal Ri Yong-ho from his posts as Chief of the General Staff of the Korean People's Army and a Vice Chairman of the party's Central Military Commission, the official Korean Central News Agency (KCNA) reported. The report made no mention of his successor nor did it provide details of his illness.

Ri, who joined the Korean People's Army in August 1959, has worked as chief of staff of a division, director of the operations department of an army corps, head of a training center, vice-director of the operations department of the General Staff, its deputy chief and the head of a training center of the KPA.

He took office as the Chief of the General Staff of the Korean People's Army (KPA) in February 2009.

He was one of the seven top North Korean officials who accompanied Kim Jong-un at the funeral procession of his father Kim Jong-il on Dec. 28 last year.

The official explanation for the illness was received with skepticism as high-ranking officials in Pyongyang customarily remain in service throughout, regardless of their health conditions, Bloomberg reported quoting Yang Moo Jin, a professor at the University of North Korean Studies in Seoul.

The sudden dismissal of Ri, one of the three key mentors tasked with equipping the rather young and inexperienced Kim to execute his duties, has been attributed to the power struggle in North Korea, largely masked from the outside world due to lack of transparency.

We cannot rule out the possibility that (Ri) was dismissed on account of Kim Jong-un's unsatisfactory grip on the military, or as a result of a power struggle in North Korea, Chang Yong-suk, an analyst at Seoul National University, told South Korea's Yonhap news agency.

Analysts voice suspicion that Ri was purged in a regime power struggle.

When Kim Jong Il was alive, Ri was at the core of laying the groundwork for the succession, so for him to be removed from every position makes it highly likely that some kind of feud has been going on in the regime, Kim Kwang-in of the North Korea Strategy Center told the Daily NK.

The Daily NK speculates that recent economic and political reforms in Pyongyang provide sufficient ground for suspicion in some quarters that the hawkish Ri was sacrificed to thwart the future efforts by military hardliners to stop reformists, or that Ri had already objected to reforms and was removed as a result.

If they (regime backers) are proposing to try for 'North Korean-style' reform and opening then they need to have complete control over the military. At the moment the Party (Workers' Party of Korea) is displaying its absolute dominance over the military, and for that nothing could be more effective than removing Ri, Daily NK writes quoting an unnamed expert in Seoul.

Analysts rule out health problems as a possible reason behind Ri's removal, since it is unprecedented in North Korea for a high-ranking officer to be removed of all posts and  attributing it to failing health.