'The old lunatic Trump'

North Korea yesterday accused Donald Trump of exploiting Otto Warmbier's death, calling the US president an "old lunatic" for alleging that the American student was tortured while in Pyongyang's custody.

In a statement issued by the official KCNA news agency, North Korea's foreign ministry attacked the US for "luring and pushing" the 22-year-old student into breaking the country's laws.

"Trump and his clique, for their anti-DPRK propaganda, are again exploiting the death of Otto Warmbier, an American college student who had been under reform through labour for the criminal act he committed against the DPRK and died after returning to the US," it said, using the acronym for the North's official name.

Warmbier, who was visiting the North as a tourist in January 2016 when he was arrested and imprisoned by the regime, died in June this year, just days after he was released from custody and sent home in a mysterious coma.

In the statement, the North accused "an anti-DPRK conspiracy organisation in the US" of sending Warmbier to the country on a criminal "mission".

"The fact that the old lunatic Trump and his riff-raff slandered the sacred dignity of our supreme leadership, using bogus data full of falsehood and fabrications, only serves to redouble the surging hatred of our army and people towards the US and their will to retaliate thousand-fold," it said.

North Korea said he had suffered no torture during his 17-month detention, a day after an Ohio coroner said he died from lack of oxygen and blood to the brain caused by an unknown injury.

Meanwhile, China said yesterday North Korean companies operating in the country will have to shut down by January as Beijing applies UN sanctions imposed following Pyongyang's sixth nuclear test.

The commerce ministry said the companies, including joint ventures with Chinese firms, have 120 days to close from the date the United Nations resolution was adopted, September 11.