North Korea's army chief has been relieved of all his posts due to illness, state media said on Monday, July 16, in a surprise development that removes one of new leader Kim Jong-Un's inner circle, according to AFP.

Ri Yong-Ho is regarded as one of the key figures who helped support the young, untested leader in the transition following the death in December of his father Kim Jong-Il, the longtime dictator of the reclusive state.

The departure and the quick announcement by the regime were "very unusual", said a spokesman of Seoul's unification ministry handling cross-border affairs, while observers say Ri may have fallen out of favor with Jong-Un.

The 69-year-old became head of the country's 1.2 million-member military – one of the world's largest – in 2009 and had been seen often accompanying Jong-Un on visits to military bases in recent months.

The North's official KCNA news agency said a meeting of top officials from the ruling party on Sunday took the decision to relieve him of his posts "for his illness".

He was removed from the "presidium of the politburo", the country's most powerful body with only a handful of members, and the "vice-chairman of the central military commission" of the ruling Workers' Party, it said.

The spokesman for Seoul's unification ministry added to reporters "We are watching the situation with interest," without elaborating further.

The general was one of seven top party and military cadres who accompanied Jong-Un when he walked alongside the hearse carrying the body of Jong-Il during his funeral.