State news agency KCNA said the man, whom it named as Bruce Byron Lowrance, had told officials he was "under the command" of USA spy agency the CIA.
Bruce Byron Lowrance has been held in North Korea for a month after illegally entering the country from China.
However, the understated announcement was more likely aimed at reassuring the North Korean military rather than trying to torpedo diplomatic talks, Asan Institute for Policy vice president Choi Kang said.
North Korea says it will deport a United States citizen who was detained in October after entering illegally from China.
The North's decision matches its general push for engagement and diplomacy with the United States this year after a string of weapons tests in 2017, and a furious US response, had some fearing war on the Korean Peninsula.
North Korean leader Kim Jong Un has overseen the testing of a "newly developed ultramodern tactical weapon", Pyongyang's state media reported Friday, in a move that will raise the temperature over denuclearization talks.
Southeast Asian-centered trade pact delayed
While negotiations to reach an agreement on RCEP have stalled, a negotiator for the pact is confident it will get across the line. But the talk in Singapore is of freer trade. "But we are very happy with that and is heading in the right direction".
North Korean Ri Jong Hyok, center, vice chairman of the Korean Asia-Pacific Peace Committee speaks during the worldwide convention for peace and prosperity in the Asia-Pacific Friday, Nov. 16, 2018 in Goyang, South Korea.
"Kim Jong Un...visited the test ground of the Academy of Defense Science and supervised a newly developed ultramodern tactical weapon test", said the official Korean Central News Agency.
Yang Wook, a Seoul-based military expert, said a "tactical weapon" in North Korea refers to "a weapon aimed at striking South Korea including USA military bases" there, so the North may have tested a short-range missile or a multiple rocket launch system.
The United States, South Korea and others have previously accused North Korea of using foreign detainees to wrest diplomatic concessions.
North Korean negotiator Kim Yong-chol cancelled a planned meeting with Secretary of State Mike Pompeo in NY last week at the last minute.
North Korea has continued to showcase its conventional military capabilities, including at a large military parade in Pyongyang, its capital, on September 9.
'Generally, tests of new high-tech weapons are conducted in secret, ' Shin said.
Israel defence minister urges early elections after resigning
Israel responded with 160 airstrikes on military targets in Gaza. "But in the security of Israel, more is hidden than known". Haniyeh further stressed that Hamas had "achieved a military victory against this odious occupier in less than a week".
U.S. Vice President Mike Pence, attending a Southeast Asian summit in Singapore, cited the "great progress" made on North Korea but said more had to be done.
USA authorities have not yet commented on the report.
A year and a half ago, "nuclear tests were taking place, missiles were flying over Japan and there were threats and propagations against our nation and nations in the region", Mr Pence said.
In separate meetings in Singapore, both Pence and Japanese Prime Minister Shinzo Abe, a close United States ally who has sought, but not been granted talks with North Korea, called for ASEAN to maintain firm sanctions pressure on North Korea. "We made great progress but there's more work to be done", he said.
Kim said the weapons system tested was one in which his father, Kim Jong Il, had taken a special interest during his lifetime, personally leading its development.
The news came nearly a year after Pyongyang's last test of an intercontinental ballistic missile and recalled the repeated announcements of 2017, which included by far its most powerful nuclear blast to date and rockets that brought the whole of the U.S. mainland into range.
Silva heaps praise on Pickford and Mina after Chelsea draw
Back in August, Richarlison picked up a three-match ban for a red card he picked up in a game away from home at Bournemouth. Hazard added: "We are in good shape in the Europa League and the Premier League and we want to keep winning".