SEOUL (REUTERS) - North Korean state media slammed former US vice-president and 2020 Democratic presidential hopeful Joe Biden for criticising leader Kim Jong Un, calling him "bereft of elementary quality as a human being".

The criticism contrasts with North Korea's repeated references to the good relationship between Mr Kim and US President Donald Trump.

Mr Kim said in April his personal relationship with Mr Trump was still good despite the collapse of their second summit in Vietnam in February.

According to Newsweek, Mr Biden said at a campaign launch in Philadelphia on Saturday: "Are we a nation that embraces dictators and tyrants like (Russian President Vladimir) Putin and Kim Jong Un?"

State media the Korean Central News Agency (KCNA) responded to criticism of the North's leadership in a commentary late on Tuesday (May 21).

"What he uttered is just sophism of an imbecile bereft of elementary quality as a human being, let alone a politician," it said.

KCNA listed previous controversies concerning Mr Biden, including allegations of plagiarism and falling asleep during a speech by former President Barack Obama in 2011.

"We will never pardon anyone who dare provoke the supreme leadership of the DPRK but will certainly make them pay for it,"KCNA said, using North Korea's official name, the Democratic People's Republic of Korea.

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Denuclearisation talks have stalled since the breakdown of the second meeting between Mr Trump and Mr Kim in February and North Korea conducted more weapons tests this month.

The tests were seen as a protest by Mr Kim after Mr Trump rejected his calls for sanctions relief at the Hanoi summit.