SEOUL/WASHINGTON - Three American citizens detained in North Korea appealed to the US government on Monday for help returning home, speaking in rare interviews with US media that were set up by the North Korean government and may signal an attempt by Pyongyang to re-open a long-stalled dialogue.The three men, one serving a 15-year sentence and two awaiting trial in the isolated country, spoke to CNN and the Associated Press in tightly controlled circumstances. One of them said his health was failing and another described his situation as "urgent."The men said they were being treated humanely but asked the US government to get more actively involved in helping resolve their situation.Responding to the interviews, the US government urged Pyongyang to release the men, and said Washington was working to try to secure their return home."Out of humanitarian concern for Jeffrey Fowle, Matthew Miller, and their families, we request the DPRK release them so they may return home," State Department spokeswoman Jen Psaki said in a statement, using the formal acronym for North Korea, and referring to the two men awaiting trial."We also request the DPRK pardon Kenneth Bae and grant him special amnesty and immediate release so he may reunite with his family and seek medical care," she added.Bae, a Christian missionary and tour operator who was arrested 18 months ago and has been sentenced to hard labour, told CNN he had spent the time "going back and forth" between a hospital and a labor camp. "I ask the US government and people out there to really put in effort to send somebody, to make it work," Bae said.The White House also said it was doing everything it could to secure the release of the three, but did not say if the men's' appeal might change Washington's approach.'STRATEGIC PATIENCE'The choreographed staging of the interviews suggests that North Korea may be looking for a way to re-open a long-stalled dialogue with Washington, possibly through the dispatch of a high-level U.S. envoy to Pyongyang.But the Obama administration is likely to tread carefully, mindful that Pyongyang has previously tried to use American prisoners as bargaining chips in talks with Washington. The White House has insisted on the prisoners' release with no strings attached and says other issues, such as North Korea's disputed nuclear program, remain separate.US officials have made clear in recent years they do not want to return to a cycle in which North Korea sparks crises that are resolved only with transactional deals. They have privately described the US policy as one of "strategic patience," which seeks to isolate North Korea and does not offer diplomatic or economic rewards for its provocations.Complicating the US approach to North Korea is what is widely believed to be limited intelligence on the country's young leader, Kim Jong Un, and the opaque workings of Pyongyang's ruling elite."We don't know much about him. I used to negotiate with the old regime, with his father's regime, you knew more or less what they wanted. But with this new guy, he's so unpredictable, you don't know where the levers of power are," said Bill Richardson, a former US ambassador to the United Nations who has travelled to North Korea in the past to help retrieve detained Americans."But it is a good sign that they structured this interview with your reporter to send these very clear messages. So I think there's a little light at the end of the tunnel," Richardson told CNN.The State Department has in the past planned to send a special envoy to Pyongyang to try to negotiate a release of Bae, insisting that the nuclear negotiations and the human rights negotiations over Bae's jailing were unrelated.North Korea has several times cancelled visits by Robert King, the US special envoy for North Korean human rights issues, to discuss Bae's case. Lacking diplomatic ties with North Korea, Washington communicates with the detained men through the Swedish Embassy in Pyongyang.TIGHTLY CONTROLLED APPEARANCESThe interviews broadcast on Monday were highly controlled, with both AP and CNN reporting that interviews were watched by North Korean officials.CNN reporter Will Ripley said North Korean authorities ferried his crew - in Pyongyang to cover a wrestling match organised by a Japanese politician - to a hotel, disclosing who it would be interviewing at the last moment.He said the officials told the crew that each interview would be conducted separately, would last five minutes and address limited topics, including any message the men might have for their families or the US government.The AP reported the detainees appeared to speak freely but cautiously. They told the news agency they did not know they were going to be interviewed until immediately beforehand.In his interview, Bae said his health was failing and he was working eight hours a day, six days a week. Sentenced on charges of attempting to bring down the state, he told CNN he was the only inmate at a prison camp staffed by more than 20 officials, including a doctor."We have always been concerned about his health, as it was clear that his severe back problems were once again hurting him as he tried to sit up for the interview," Bae's sister, Terri Chung, said in a statement."My family sincerely appreciates the efforts put forth on behalf of my brother. The time is now - respectfully - to step up every diplomatic effort to release Kenneth, a US citizen."Miller and Fowle, who were arrested this year while on tourist visits, said they were being treated well as they awaited trial."My situation is very urgent," said Miller, 24, from Bakersfield, California, who was arrested in April when he ripped up his tourist visa on entry to North Korea and said he was seeking asylum, state media said at the time."Very soon I am going to trial, and I (will) directly be sent to prison," Miller said. He declined comment on why he wanted to seek asylum in North Korea.Fowle, a middle-aged man from Miamisburg, Ohio, said he was being treated well: "I hope and pray that it continues, while I'm here, two more days or two more decades." He was arrested in May after he left a Bible under a bin in the toilet of a sailor's club in the northeastern city of Chongjin.