Pyongyang says Thae Yong-ho embezzled state funds, raped a minor and spied for South Korea in exchange for money.
North Korea has accused one of its most senior diplomats, who defected to South Korea, of being a "criminal" involved in "embezzlement" and other serious offences, in an effort to discredit him.
Pyongyang’s Korean Central News Agency (KCNA) said that Thae Yong-ho, who they described as "human scum", had embezzled state funds, raped a minor and spied for South Korea in exchange for money.
The report did not name the "diplomat who fled his mission in London" but it was apparently referring to Thae, who defected while in Britain.
Thae is one of the highest ranking North Korean diplomats ever to defect to the South, gifting Seoul a major propaganda coup at a time of rising tension on the divided Korean peninsula.
Any defection by a ranking member of an overseas North Korean mission would make waves, but London is considered a particularly prestigious posting that puts Thae’s flight on a whole different level.
KCNA also criticised Britain for handing over Thae and his family to South Korea, saying that Pyongyang had previously told London of his crimes and requested his extradition.
The news agency’s comments mark Pyongyang’s first public response to the high-level defection, which is a rare and damaging loss of diplomatic face for the North.
Seoul said earlier this week that Thae’s defection reflected a loss of faith among North Korea’s elite in Kim Jong-Un’s leadership.
Thae had become disillusioned with the Pyongyang regime, admired South Korea’s free and democratic system, and was concerned about his family’s future, the South’s Unification Ministry said after the defection.
KCNA said Thae had fled "for fear of legal punishment for his crimes", adding that the South had brought the "fugitive" to Seoul to use him in its anti-Pyongyang smear campaign.
"He deserved a legal punishment for his crimes, but he took to flight, betraying his country and parents and other kith and kin," KCNA said.
The defection is likely to strain already-fraught relations between South and North Korea. The two sides are officially still at war since the Korean War in the 1950s ended in a truce rather than a peace deal.
Many North Koreans flee the country each year because of famine and repression. Most cross the border into China or travel via other countries to South Korea.
In April, a group of 13 North Koreans who worked in the same restaurant in an unspecified country defected to South Korea.