North Korea has sacked Pak Jong Chon, the second most powerful military official after leader Kim Jong Un, state media has reported.

Pak, vice chairman of the Central Military Commission of the ruling Workers' Party and a secretary of the party's Central Committee, was replaced by Ri Yong Gil at the committee's annual meeting last week, the state-run KCNA news agency said on Sunday.

No reason for the change was given. Pyongyang regularly revamps its leadership and the year-end party gathering has often been used to announce personnel reshuffles and major policy decisions.