Pyongyang's official Korean Central News Agency said the former USA vice president had insulted the country's supreme leadership and committed an "intolerable and serious politically-motivated provocation".
North Korea's U.N. Ambassador Kim Song held a rare news conference at the United Nations in NY to demand the immediate return of the ship, which the United States said earlier this month it had seized over accusations it was used for coal shipments in violation of USA and U.N. sanctions.
Kim, the ambassador, told reporters that the ship seizure is the "product of an extreme hostile policy of the United States against the DPRK", the initials of the country's official name, the Democratic People's Republic of Korea.
"What he uttered is just sophism of an imbecile bereft of elementary quality as a human being, let alone a politician", the statement said. -North Korea summit in Singapore last June, ended early when Trump walked away.
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KCNA is renowned for its criticism of former US President Barack Obama's ex-righthand man. He recently slammed Kim as a thug.
He also spoke about Kim as "a guy with his uncle's brains blown out, sitting across a table" referring to the 2013 execution of Jang Song-thaek, Kim's uncle and an important figure in the Pyongyang regime. But it did appear to give a nod to Trump's newly rolled out nickname for Biden: "Sleepy Joe".
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KCNA also hit at Biden's reputation for making verbal gaffes. "He is self-praising himself as being the most popular presidential candidate". "This is enough to make a cat laugh", the report said.
It was the first time the USA had seized a North Korean vessel after several years of close calls on the high seas in which the country's shippers renamed their vessels, used false flags and turned off their tracking devices to avoid detection.
Shortly after North Korea's launch of short-range missiles on May 9th, the U.S. Justice Department announced it had impounded the "Wise Honest". He has repeatedly talked about his good personal relationship with Kim.
This was the first USA seizure of a North Korean vessel for violating worldwide sanctions.
"We are condemning in strongest terms this act of dispossessing of our cargo ship".
The Trump administration must make a "big decision" on lifting sanctions before stalled nuclear negotiations can resume, Han Tae Song, North Korea's ambassador to the U.N.in Geneva, added in an interview.
A second summit between the two leaders in late February 2019 in Vietnam collapsed over mismatched demands in sanctions relief and disarmament. The summit collapsed without an agreement as the North wanted to see key US -led United Nations sanctions lifted while the USA did not find the proposed denuclearization measures sufficient.
He ended the news conference saying: "We'll sharply watch the reaction of the United States".