BOGOTA, Colombia -- A former U.S. Marine who Colombia's main insurgency says it "captured" a month ago in a turbulent southeastern region is a tourist, not a member of the U.S. mission, and should be released immediately, Washington's ambassador said Saturday.
A Colombian police general said Kevin Scott Sutay, 26, had entered a hot zone against warnings.
The rebels offered to free Sutay as a good-faith gesture in announcing on their website Friday night that he was in their custody.
The Revolutionary Armed Forces of Colombia, or FARC, said Sutay had described himself as a 2010-11 veteran of the Afghan conflict who left the armed forces in March.
It did not say how it came to have Sutay but suggested he was "a mercenary."
U.S. Ambassador Michael McKinley denied that and also said Sutay was not an active member of the military.
"We understand that (he) was on a trip as a private citizen through Latin America," the ambassador told reporters when questioned about Sutay after attending a Mass marking Colombia's independence day. "He is a citizen who has nothing to do with Colombia's internal conflict."
The chief of Colombia's anti-kidnapping police, Gen Humberto Guatibonza, told The Associated Press that Sutay had spent from June 11-13 in the Las Palmas hotel in San Jose del Guaviare, where a Colombian military base is located, then attempted land travel to Puerto Inirida, capital of the eastern state of Guainia on Venezuela's border.
Guatibonza said Sutay wouldn't heed the advice of hotel workers to fly to Puerto Inirida so they notified the police. He described Sutay as a thin, tall man with a military-style haircut .
Hotel officials and police told him "the area was dangerous," said Guatibonza, but he ignored them. He said local anti-kidnapping police had him sign a statement saying he took responsibility for his action.
The FARC has three active fronts in the region and said it captured Sutay on June 20 in the nearby town of Retorno.
The Pentagon on Saturday referred queries about Sutay's military background to the U.S. State Department and the embassy in Bogota. An embassy spokeswoman, Erika Avila, said she had no additional information to offer.
The U.S. military has long assisted Colombia's armed forces, including with sophisticated weapons and intelligence, and at any given time has dozens of uniformed personnel as well as civilian contractors in the country.
Three U.S. military contractors held by the FARC for more than six years were rescued in 2008, along with former presidential candidate Ingrid Betancourt and a group of Colombian soldiers and police.
The FARC said Sutay identified himself as anti-mining and explosives specialist.
It said Sutay's passport says he was born in New York City. It published what it said was the passport number and date of issue. It also said he arrived in Colombia on June 8 after traveling through Mexico, Honduras, Costa Rica, Nicaragua and Panama.
The group said it would free Sutay in light of peace talks going on in Cuba to end Colombia's nearly half-century-old conflict. Those talks began in November and the U.S. government has been wholly supportive of them. One condition for the talks was that the FARC halt ransom kidnapping.
The FARC in its statement asked that a commission be convened led by former Sen. Piedad Cordoba, who has in the past brokered prisoner releases, and include a delegate of the International Committee of the Red Cross.
Cordoba said Saturday on the website of a movement she backs that she stands ready to help in whatever way possible to secure Sutay's hasty release.
The FARC has in the past used such releases for publicity purposes, mounting a show as it did last year for the release of a French journalist.
Colombia's army said Saturday that four of its soldiers had been killed during clashes with FARC guerrillas in the south and it feared 14 other soldiers had died in an ambush in the northwest.
The army said six FARC rebels were killed in the fighting in the south, which involved a series of gunbattles that began Friday and continued near the town of Doncello.
Gen. Javier Rey, director of army operations, told the AP that the reported loss of 14 soldiers in an ambush in the northwestern Arauca department had not been confirmed. Rey said preliminary reports indicated troops were attacked by Colombia's other rebel group, the National Liberation Army, but noted that FARC guerrillas also operate in that area.
-- Associated Press writer Frank Bajak in Lima, Peru, contributed to this report.