North Korea denies torturing US student Otto Warmbier

North Korea has denied torturing US student Otto Warmbier who died days after being released in a coma a year into a 15-year sentence for stealing a poster.

In an article published by the official Korean Central News Agency (KCNA) Pyongyang said they treated the 22-year-old according to domestic law and international standards.

The statement said the country was being subjected to a "smear campaign" and described themselves as the "biggest victims" in the incident.

"The smear campaign against DPRK staged in the US compels us to make firm determination that humanitarianism and benevolence for the enemy are a taboo and we should further sharpen the blade of law," the spokesman added, referring to North Korea by its formal name, the Democratic People's Republic of Korea.

"To make it clear, we are the biggest victim of this incident and there would be no more foolish judgment than to think we do not know how to calculate gains and losses," the spokesman said.

The article also criticised South Korea for using Mr Warmbier's case to seek the release of other detainees.

Mr Warmbier was flown home in a coma after being released for what was described as humanitarian reasons. He died on Monday in a US hospital.

He had been accused of stealing a propaganda poster and was serving 15 years in prison with hard labour.

His family and others have blamed North Korea for his condition, saying he was "brutalised and terrorised by the pariah regime" .

But in its first statement since the University of Virginia undergraduate's death, North Korea refuted the accusations.

The agency said: "Our related institutions are treating criminals who committed crimes against (our) republic strictly based on domestic law and international standards, and Warmbier was no different," the KCNA said.

It also accused Seoul of tarnishing Pyongyang's image with its "slanderous talk about cruel treatment and torture" while having no knowledge of the "humanitarian" treatment Mr Warmbier received in the North.

US doctors said Mr Warmbier had suffered a severe neurological injury from an unknown cause.

The agency did not provide further details on how Mr Warmbier was treated under detention or what might have caused him to lapse into a coma.