North Korea's army chief of staff has been executed, South Korean media reported Wednesday, in what would amount to the latest in a series of purges and executions of top officials by leader Kim Jong-Un.

Ri Yong-Gil, Chief of the Korean People's Army (KPA) General Staff was executed earlier this month for forming a political faction and corruption, Yonhap news agency said, citing a source familiar with North Korean affairs.

The report came at a time of highly elevated tensions on the divided Korean peninsula following the North's recent nuclear test and long-range rocket launch.

Ri was often seen accompanying Kim Jong-Un on inspection tours, but his name was conspicuously missing from state media reports of a recent major party meeting and celebrations over Sunday's rocket launch.

"The execution... suggests that Kim Jong-Un still feels insecure about his grip on the country's powerful military," Yonhap quoted the source as saying.

"It shows that Kim's reign of terror still persists," the source was quoted as saying.

The National Intelligence Service (NIS) in Seoul declined to comment on the report.

In May last year the NIS said Kim had his defence chief, Hyon Yong-Chol, executed -- reportedly with the use of an anti-aircraft gun.

Hyon's fate was never confirmed by Pyongyang but he has never been seen or heard of since. Some analysts have suggested he was purged and imprisoned.

Reports -- some confirmed, some not -- of purges, executions and disappearances have been common since Kim took power following the death of his father Kim Jong-Il in December 2011.

A large number of senior officials, especially military cadres, were removed or demoted as the young leader sought to solidify his control over the powerful army.

In the most high-profile case, Kim had his influential uncle, Jang Song-Thaek, executed in December 2013 for charges including treason and corruption.