One of the topics that will be brought up during the U.S.-North Korea summit is the release of three American detainees held captive by the regime. <br /> The AP reports, citing White House officials,... that the issue was raised by CIA Director Mike Pompeo during his recent meeting with North Korean leader Kim Jong-un in Pyongyang.<br />Also addressing reporters alongside visiting Japanese Prime Minister Shinzo Abe this week, President Trump said the U.S. is working (quote) "very diligently" to free the Americans.<br /> The three American detainees are Kim Hak-song , Tony Kim and Kim Dong-chul .<br />Concern for all three has grown after a fourth American detainee, Otto Warmbier, died shortly after he was released from North Korean custody last summer. <br />