The US is attempting to confirm reports that North Korea has executed its special envoy to America, Secretary of State Mike Pompeo has said.

“We’ve seen the reporting to which you are referring,” Mr Pompeo told a news conference in Berlin. “We’re doing our best to check it out."

South Korean media reported that the secretive communist state had executed Kim Hyok-Chol and other foreign ministry workers who steered negotiations for a failed summit between leader Kim Jong-un and US President Donald Trump.

The pair met in the Vietnamese capital of Hanoi in February to discuss the denuclearisation of North Korea in exchange for some possible sanctions relief. But the talks stalled and the summit was abruptly cut short by several hours.

North Korea has reportedly executed several officials who carried out talks after charging them with spying for the US.

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Kim Hyok-Chol, North Korea’s special representative for US affairs, was executed by firing squad in March, South Korea’s largest daily Chosun Ilbo reported, citing an anonymous source.

It quoted the unnamed North Korean official as said that Mr Kim "was investigated and executed at Mirim Airport with four foreign ministry officials".

Shin Hye-Yong, the interpreter for Kim Jong-un at the meeting, is also said to have been detained in a political prison camp for undermining the authority of the leader by making a critical interpretation mistake, the newspaper reported.

Mr Kim’s sister, Kim Yo-jong, who aided the leader in Hanoi, is also said to be lying low.

Kim Yong-Chol, Kim Jong-un’s right-hand man and a senior Workers’ Party vice chairman who visited the White House as the main point man for diplomacy with the United States, has reportedly also been subjected to forced labour and ideological education in a remote province near the Chinese border.

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Some previous South Korean reports of North Korean purges and executions have later proved inaccurate.

Asked about reports of a “shakeup” of Kim Jong Un’s negotiating team in a 5 May interview with ABC News, Mr Pompeo said it did appear that his future counterpart would be somebody.

However, he added: "We don’t know that for sure.”