North Korean Official's Possible Execution the Source of Heated Speculation Differing accounts regarding N. Korea defense chief's well-being have emerged.

SEOUL -- Speculation swirled today over whether North Korea’s second highest-ranking defense chief has been publicly executed. Adding to the confusion, South Korea’s National Intelligence Service (NIS) gave two different accounts to the Intelligence Committee at the National Assembly this morning and later at a press briefing.

The top spy agency told lawmakers at a closed briefing that Hyon Yong-chol, Minister of the People’s Armed Forces, was executed April 29 or 30 by anti-aircraft machine guns at a military training area 13 miles north of Pyongyang in front of hundreds of high-level military officials.

“We were told that according to collected information, the NIS believes Hyon was publicly executed for behaving disrespectfully despite Kim Jong-un’s previous warnings and also for dozing off at official events,” said Kim Kwang-jin, national assemblyman who was at the briefing.

North Korea’s state Rodong Newspaper posted a photo April 26 of Hyon sitting close to Kim at an event with his eyes closed. It is unclear whether the photo was taken when he was looking down or falling asleep.

Hyon was last spotted April 28 attending a music concert by Pyongyang’s Moranbong Band but was absent two days later when North Korean leader Kim Jong-un was taking an official photo at a military training event.

“When we were briefed of that absence on the 30th being cited as one of the plausible evidence, I had doubts,” said Shin Kyoung-min, another national assemblyman. “We’ve seen Hyun even yesterday on TV. If North Korea really executed their number-two man in charge of defense, they would make sure he disappears on every single program. That’s definitely their style.”

Assemblyman Shin told ABC News he repeatedly questioned the analysis but NIS confirmed they “checked with various channels” and “Hyon has been indeed executed,” adding that unlike the previous execution of Kim’s uncle Jang Song-thaek, this one was taken care of within two or three days of his arrest and without proper trial.

Reports of such a brutal execution of a prominent top defense chief in North Korea immediately made top news but sparked doubts and questions over the authenticity of the information.

The NIS in the afternoon then backed down from the earlier briefing to the National Assembly, giving a different account to the press.

“We confirm that Hyon Yong-chol was purged [not executed]. We do have intelligence information that he had been killed by gunfire but that is yet to be verified,” a spokesman for the NIS told ABC News.

The South Korean spy agency has made erroneous predictions over North Korean affairs in the past, including Kim Jong-un’s presumed visit to Russia, Pyongyang’s long-range missile test in 2012 and Kim Jong-il’s death in 2011.

“The question right now is whether the NIS report is reliable. There are several basic principles when analyzing movements in North Korea’s core elites but NIS analysis does not make sense when Hyon is still appearing on their documentaries,” said Cheong Seong-chang, a senior North Korea expert at Sejong Institute. “The confusion is multiplying because NIS is relying on uncertain intelligence information.”

Hyon rose to a power post as a four-star general in 2010 on the same day when Kim Jong-un was officially anointed as vice chairman of the Central Military Commission, Kim’s first political debut. Hyon then replaced Ri Yong-ho, a powerful former army chief in July 2012, and became a member of North Korea’s National Defense Commission last year.

ABC News’ Yoon-geon Hong, Jiwon Choi and Yeon Joo Lee contributed to this report.