A Kazakh border guard confessed to killing 14 of his fellow servicemen at a remote frontier post, blaming internal conflicts and a mental breakdown, the prosecutor-general's office said Thursday.

But a Kazakh television presenter said he had resigned rather than read out the official scenario, calling it "nonsense."

The 14 guards were found dead in the burnt-out ruins of their post close to the Chinese border last week. The sole survivor, Vladislav Chelakh, was found sheltering in a herdsman's hut Monday.

Chelakh on the same day "confessed to murdering his fellow servicemen," the prosecutor-general's office said in a statement.

"According to Chelakh, his motive was internal conflicts and an inexplicable condition in which his mental state was clouded," it said without elaborating.

The newsreader for Channel 31 television, Vladislav Dlinnov, wrote on Twitter, "I refuse to lie on air and talk nonsense about how a border guard 'confessed' to murdering his fellow servicemen.

"Will any journalist or newsreader seriously read this news on air? It's a disgrace."

Chelakh was cited as telling investigators that he had keys to open a safe containing weapons at around 5:00 am on May 28. He shot a patrol guard before returning to the barracks and shooting sleeping guards and the commander.

Many did not defend themselves because they thought he was joking, he told investigators. Prosecutors said he was armed with a pistol and a machine gun.

Finally, he shot a huntsman acting as a security guard, his 15th victim.

He then sprayed machine gun fire around the barracks to make the source of the attack unclear and set fire to the building.

He fled in civilian clothing, carrying a pistol and a computer and cell phones belonging to other guards.

His mother, Svetlana Vashchenko, told AFP that nothing had indicated anything was wrong with her son's service.

"He had wanted to serve on the border so much and was so proud that he got sent to a good post."

"I have no words," she added. "I can't even see him and I don't know when I will be able to. I don't even know whether he has lawyers."

The prosecutor-general's office said that Chelakh would undergo psychological testing.

The Vremya newspaper, an official mouthpiece, reported Thursday that investigators examining the victims found one was wearing women's underwear, but this was later denied by a spokesman for the prosecutor-general's office.

Kazakhstan held a day of mourning for the victims on Tuesday.

The government had initially branded the murders as an "act of terror."

The bodies were found on May 30 in the burnt-out remains of the Argkankergen border control post at a height of around 3,000 metres (9,800 feet) in the mountains outside Kazakhstan's biggest city Almaty.