North Korea has freed three US citizens from prison, according to a tweet from US President Donald Trump. It is viewed as a goodwill gesture ahead of a historic summit between Mr Trump and North Korea's Kim Jong-un. Mr Trump said he would greet the men when they return with Secretary of State Mike Pompeo, who has been in Pyongyang to arrange the planned talks. Kim Hak-song, Tony Kim and Kim Dong-chu were able to "walk on the plane without assistance", the White House said. They had been jailed for anti-state activities and placed in labour camps. Mr Trump announced the release of the men in a tweet on Wednesday.