|north korea leader|
Hyon Yong Chol was killed by firing squad using an anti-aircraft gun at a military school in front of hundreds of people in Pyongyang around April 30, the agency reported, citing a media briefing by the National Intelligence Service at its headquarters in Seoul.
Hyon "was purged for lese majeste" because he was seen "dozing off" during a military event and "did not carry out Kim's instructions," the agency said. It wasn't clear what instructions Hyon failed to carry out.
The intelligence service told politicians that Hyon was killed by an anti-aircraft gun at Kang Kon Military Academy - a method cited in various unconfirmed reports as being reserved for senior officials who the leadership wishes to make examples of.
The execution was initially reported by South Korea's Yonhap news agency, although reports from North Korea are impossible to independently confirm.
Hyon is believed to have been a general since 2010 and served on the committee for late leader Kim Jong-il's funeral in December 2011, before becoming defence minister.
North Korean leader Kim Jong Un has been accused of ordering the executions of as many as 15 top officials so far this year.