TOKYO — North Korea on Saturday acknowledged that it is holding an elderly U.S. citizen and said he had apologized for committing a “long list of indelible crimes” during the Korean War six decades ago. It did not indicate whether the citizen, Merrill E. Newman, would be released.

Newman, 85, has been held in the North for more than a month after being removed from an outgoing plane at the end of a tourist trip he had taken with a friend from his retirement community in California.

After weeks of silence, the North’s state-run Korean Central News Agency on Saturday released a flurry of information on Newman’s case, including what it described as a letter from Newman detailing his violations during the war. It also released a brief video of Newman, wearing khakis and a green button-down shirt, reading from the letter and marking it with an inked thumbprint.

Although there was no immediate way to gauge the letter’s authenticity, previous detainees in the North have said they were coerced into writing apologetic letters. Newman’s letter, filled with grammatical errors and perplexing run-on sentences, appeared to be written by a nonnative English speaker.

“I realize that I cannot be forgiven for my offensives,” the letter says, “but I beg for pardon on my knees by apologizing for my offensives sincerely toward the North Korean government and the Korean people and I want not punish me (sic).”

Newman’s family members have told the media in recent weeks that the retired technology executive from Palo Alto, Calif., served in the military during the Korean War and wanted to return to see the North as a tourist. The friend who traveled with Newman, Bob Hamrdla, said in a statement that his detention had to stem from a “terrible misunderstanding.”

The KCNA news agency, in a separate article detailing Newman’s alleged crimes, said Saturday that Newman had led espionage activities against the North and was involved in the killing of military personnel and civilians.

Newman’s supposed letter says that he served in the intelligence bureau of the U.S. Far East Command and helped spearhead attacks on communications systems, railroads and food storage areas. It also says that during his tourist trip, he had hoped to visit old war sites and connect survivors with an anti-communist group. The letter, dated Nov. 9, sheds no light on the conditions of Newman’s detainment.

Since 2009, North Korea has detained at least seven U.S. citizens, including Kenneth Bae, who has been held for more than a year. The others were granted releases, but in some cases only after high-profile rescue missions, including trips by former presidents Jimmy Carter and Bill Clinton.

The United States does not maintain diplomatic relations with North Korea, and depends on Swedish diplomats in Pyongyang as proxies.

Shortly after Newman’s detention, the State Department recommended that U.S. citizens refrain from visiting the North.