The United States Thursday signaled that North Korea could improve its strained ties with Washington by releasing U.S. citizens held by Pyongyang. North Korea last month detained Merrill Newman, an 85-year-old veteran of the Korean War, taking him off a plane as he was about to leave the Asian country, which he had been visiting on a tourist visa. North Korea has also held Kenneth Bae since November 2012, sentencing him to 15 years of hard labor. "North Korea could send a very different signal about its interest in having a different sort of relationship with the United States were it to take that step of releasing our citizens," Glyn Davies, U.S. special representative for North Korea policy, told reporters in Beijing.