Death of US student Otto Warmbier 'a mystery to us too', says North Korea

North Korea has described the death of Otto Warmbier as a “mystery” and denied it had used cruel treatment and torture on the US student.

Pyongyang also said that Mr Warmbier, who died on Monday after being held in the reclusive state for 18 months, was "a victim of the policy of strategic patience” under former US president Barack Obama, whose administration never requested his return.

"The fact that Warmbier died suddenly in less than a week just after his return to the US in his normal state of health indicators is a mystery to us as well," a foreign ministry spokesman was quoted by Korean Central News Agency (KCNA) as saying.

Mr Warmbier was arrested for stealing a propaganda poster from a hotel and sentenced to 15 years hard labour in March 2016.

He was returned to the US shortly before his death after being released with brain damage. The exact cause of Warmbier's death remains unclear. 

"Although Warmbier was a criminal who committed a hostile act against the DPRK, we accepted the repeated requests of the present US administration and, in consideration of his bad health, sent him back home on humanitarian grounds," the spokesman said.

KCNA accused South Korea of making "slanderous talk about cruel treatment and torture" of Mr Warmbier.

“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," KCNA said.

North Korea ramps up missile efforts

Meanwhile, North Korea appears to be ramping up its efforts to build a missile which can reach the US mainland with the test of a new rocket engine which could be used for a long-range projectile.

A US official said the test could be for “the smallest stage of an intercontinental ballistic missile (ICBM) rocket engine”, according to Reuters news agency.

If confirmed, the test would be the latest action by Kim Jong-un’s regime indicating that it is rapidly pressing ahead with its weapons programme.

Donald Trump’s administration have become increasingly frustrated with the North’s military build-up, declaring that Washington’s policy of “strategic patience” towards Pyongyang was at an end.

In pressuring North Korea, Mr Trump had sought the help of China, the reclusive state’s only diplomatic ally and key trading partner.

However, earlier this week the US President tweeted that China’s efforts in steering North Korea away from its military ambitions had “not worked out”.

Despite concerns over the apparent lack of progress, Yang Jiechi, China’s top diplomat, told Mr Trump that Beijing would continue to work with Washington on confronting Pyongyang’s nuclear ambitions.

He said in a meeting in Washington on Thursday that China would “promote the early realisation of the denuclearization of the (Korean) peninsula”, a statement from China’s foreign ministry said on Friday.

The meeting between the pair was not disclosed by US officials.

The Chinese diplomat also told Mr Trump: “China is willing to continue its efforts to maintain communication and coordination with relevant parties, including the United States, to jointly ease the tensions on the peninsula and promote the proper settlement of the Peninsula nuclear issue.”

Additional reporting by Christine Wei