Donald Trump made history on Sunday by becoming the first U.S. president to set foot in North Korea . He briefly entered the Stalinist state during a meeting with Kim Jong-un at the demilitarized zone where both leaders agreed to resume talks on decnuclearization . In the wake of that breakthrough, North Korea have now suddenly accused the U.S. of being "hell-bent on hostile acts". The sudden complaint was made after the U.S. sent a letter together with the UK, France and Germany to all UN member states, urging them to send North Korean migrant workers back by the end of the year.The letter was penned on June 29, the day Trump tweeted that he wanted to meet Kim at the DMZ in order to shake hands. The world of North Korean laborers abroad is a shadowy one and thousands of them get sent to different countries around the world to generate hard currency for the regime. Website "North Korea in the World" maintains statistics about the countries hosting the migrant workers.Most of them go to China and Russia which are estimated to host a maximum of 80,000 and 40,000 laborers respectively. The vast majority of them are employed in construction, agriculture, logging, garment-making and traditional medicine while a smaller number are known to work in North Korean restaurants. Altogether, it is believed that 41 countries host or have recently hosted North Korea's migrant workers.