North Korea has executed five officials for their part in the failed second summit between President Trump and North Korean leader Kim Jong Un, according to a South Korean newspaper.

Citing the newspaper, Bloomberg News reported that Kim Hyok Chol, North Korea’s special envoy to the U.S., was executed by firing squad in March for being “won over by the American imperialists to betray the supreme leader.”

The paper also claimed that four other North Korean Foreign Ministry officials were executed that same month because of the breakdown of the February summit in Hanoi, Vietnam, but did not provide details.

Trump’s much-anticipated summit with Kim ended abruptly and without the two leaders signing any agreements over nuclear disarmament.

Top Kim aide Kim Yong Chol is reportedly undergoing hard labor for his role in the breakdown.

He had been Kim’s most trusted policy adviser and was removed from one of his posts.