The State Department has not confirmed the identity of the man, but the family of Merrill Newman, of Palo Alto, Calif., says he has been detained in North Korea since Oct. 26, CNN reported.
State Department spokeswoman Jennifer Psaki said because the United States does not have diplomatic relations with North Korea, the State Department is working with Sweden to have the man released.
"We are working in close coordination with representatives of the Embassy of Sweden to resolve this issue, and they also have requested on a daily basis consular access," Psaki told reporters Friday.
Newman's wife, Lee, released a statement urging the release of her husband.
"The family feels there has been some dreadful misunderstanding leading to his detention and asks that (North Korea) work to settle this issue quickly and to return this 85-year-old grandfather to his anxious, concerned family," the statement said.
Merrill Newman, who had been on a 10-day organized private tour of North Korea with a friend, was last seen aboard a flight from Pyongyang to Beijing in October, his family said.
He was removed from the flight shortly before takeoff and has been detained in North Korea since then.
"We have had no word on the state of his health, whether or not the medications sent to him through the Swedish Embassy in North Korea have been delivered or why he was detained," Lee Newman's statement said.