North Korea denies torturing US student.

North Korea has denied torturing US student Otto Warmbier in 

the first official reaction since the US student died after returning 

home in a coma.

The hermit state broke its silence after South Korea said the North

 bore responsibility for Warmbier's fate and President Donald Trump

 slammed his detention and death as 'a total disgrace'.

Its official news agency, KCNA, quoted a government source as saying:

 'Our relevant agencies treat all criminals in accordance with domestic

 laws and international standards and Warmbier was not an exception.'

It blamed accusations of mistreatment on an American 'smear campaign' 

and accused South Korean of seeking to exploit Warmbier's death 

to press its own demand for the release of six detainees.

Warmbier, 22, died in a US hospital on Monday after North Korea 

released him for what it called humanitarian reasons.

Doctors at the hospital said he had suffered a severe neurological

injury from an unknown cause.

The University of Virginia student is thought to have been in a

 coma since he was sentenced to 15 years of hard labor for

 stealing a propaganda poster in March 2016.

His family and others have blamed North Korea for his condition. 

South Korean President Moon Jae-in told CBS television earlier this

 week that it was clear North Korea bears a heavy responsibility for 

Warmbier's death.

KCNA said the North dealt with him according to its domestic 

laws and international standards.

It accused South Korea of 'slanderous talk about cruel treatment and torture' while having no knowledge of the 'humanitarian' treatment Warmbier received.

KCNA didn't provide details of how Warmbier was treated or what might have caused him to lapse into a coma.

It demanded that South Korea return 12 restaurant workers who defected to the South last year. 

South Korea said the women defected on their own, while North Korea claimed they were deceived and abducted to the South.

The United States, South Korea and others often accuse North Korea of using foreign detainees to wrest diplomatic concessions. 

Three Americans remain in custody in the North.