Published: Nov 21, 2013 7:32 AM EST

PASADENA, Calif. (AP) - An 85-year-old American veteran of the Korean War was detained last month in North Korea as he sat in a plane set to leave the country, his son said Wednesday.
    
Merrill Newman of Palo Alto, Calif. was about to leave the country on Oct. 26 when a uniformed North Korean officer came on the plane, asked to see his passport, and asked the stewardess to have him leave the plane," Jeffrey Newman said.
    
"My dad got off, walked out with the stewardess, and that's the last he was seen," Jeffrey Newman told The Associated Press at his home in Pasadena, Calif.
    
Merrill Newman was traveling with friend Bob Hamrdla, who was allowed to return.
    
Hamrdla said in a statement that "there has to be a terrible misunderstanding. I hope that the North Koreans will see this as a humanitarian matter and allow him to return to his family as soon as possible."
    
The U.S. State Department wouldn't confirm the detention, first reported by the San Jose Mercury News, and North Korea's state media has yet to comment.
    
Jeffrey Newman said his father was a constant traveler but had always wanted to visit North Korea, and took lessons in the language before leaving on the nine-day trip.
    
"This has been a lifelong dream of his," Jeffrey Newman said.
    
Newman said he believed the desire for the trip came from the three years his father spent as an infantry officer in the Korean war, but said Merrill Newman never talked about his service.
    
Jeffrey Newman said he'd had received postcards from his father saying the trip was going well, but on the last day of the tour, according to Hamrdla, Merrill Newman met with North Korean officials and he came away with some uneasy feelings.
    
"We think that the conversation was difficult at times," Newman said, but did not know details.
    
Because the United States has no diplomatic relations with North Korea, Jeffrey Newman says the family has been working through State Department officials and the Swedish Embassy to secure his father's freedom.
    
The Swedish ambassador also delivered his father's heart medication to the North Korean Foreign Affairs Ministry, but it's unclear whether he had received it.
    
The State Department on Tuesday heightened a travel warning for North Korea but did not link the advisory to Newman's detainment or even confirm he is being held.
    
The detention comes about a year after North Korea detained another American. North Korea has detained at least six other Americans since 2009.
    
Pyongyang's secretive, authoritarian government is sensitive about foreign travelers, and tourists are closely monitored. The North has previously accused Seoul, Washington and other outsiders of working to sabotage its system - statements that analysts see as a way to strengthen domestic support for young leader Kim Jong Un.
    
North Korea's official state-run media has yet to comment, and South Korean officials said they couldn't confirm media reports.
    
Merrill Newman has lived in a retirement complex with his wife, Lee, since 2011 in Palo Alto, where he's a big part of the alumni community at nearby Stanford University, his son said.
    
Jeffrey Newman said he believed North Korea would eventually release him after realizing that all they have is an "elderly traveler, a grandfather with a heart condition."
    
"We don't know what this misunderstanding is all about," Jeffrey Newman said. "All we want as a family is to have my father, my kids' grandfather, returned to California so he can be with his family for Thanksgiving."
    
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AP reporter Channing Joseph contributed to this report from San Francisco.

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