The US is to ban its citizens from travelling to North Korea, according to two agencies that operate tours there. Koryo Tours and Young Pioneer Tours said the ban would be announced on 27 July to come into effect 30 days later. The US has not confirmed the news. Young Pioneer Tours was the agency that took US student Otto Warmbier to North Korea. He was later arrested and jailed for 15 years, before being returned in a coma to the US in June. He died a few days later.