(CNN) -- In a secret operation a U.S. official called "brilliant," the Colombian military infiltrated rebel group FARC and deceived its members into giving up 15 hostages including former Colombian presidential candidate Ingrid Betancourt, Colombia's defense ministry said.
Betancourt, who was reportedly in deteriorating health, was kidnapped in 2002 by the Revolutionary Armed Forces of Colombia, or FARC.
Along with Betancourt, three American contractors and 11 other hostages who were Colombian police were rescued in Wednesday's operation.
Colombian Defense Minister Juan Manuel Santos said the Colombian military had infiltrated the FARC leadership and arranged for the hostages to be taken to the south of the country, where they were to be picked up by helicopters that the rebels believed were controlled by another group.
The Colombian military helicopters flew the 15 away without violence. They were initially transported to a military air base southwest of Bogota, from which they were to travel later Wednesday to the capital, a military spokesman said.
Santos called the operation unprecedented and said it "will go into history for its audacity and effectiveness," according to The Associated Press.
The AP also reported that Betancourt said the "absolutely impeccable" military mission took her by surprise and "got us out grandly." She and the other hostages didn't know that military intelligence agents were flying the helicopters that the hostages thought were taking them to another rebel camp, the AP said.
The FARC, which has fought a longstanding and complicated conflict with Colombia's government and right-wing paramilitary groups, defends the taking of captives as a legitimate act of war and is believed to hold roughly 750 prisoners in the nation's remote jungles.
The freed include Americans Keith Stansell, Marc Gonsalves and Thomas Howes.
A senior U.S. State Department official told CNN that the families of the hostages had no idea that the rescue operation was taking place.
The plight of Betancourt, who has French and Colombian citizenship, has attracted worldwide attention.
She was abducted February 23, 2002, after venturing into rebel territory while campaigning for the Colombian presidency. Videos later showed a slim Betancourt, sitting silently in a jungle setting.
News of her deteriorating health came after the FARC released six hostages this year. One of the freed hostages, Luis Eladio Perez, said that Betancourt had suffered from chronic liver problems since 2004.
He said he last saw her February 4 this year.
"Ingrid made a sign for me to go to the bathroom, and she did the same, and we were able to talk for about five minutes," Perez said. "I saw she was very ill and wasting away. She looked much worse than in that 'proof-of-life' video the rebels filmed in October."
Betancourt "seemed desperate," even though "she told me to stay calm and that the guerillas were giving her vitamins and calcium," he said.
French President Nicolas Sarkozy expressed gratitude to Colombian authorities and said Betancourt "is in good health."
Betancourt's jubilant daughter, Melanie Delloye, said, "I feel like I've just awakened from a bad dream."
She and other members of the family spoke alongside Sarkozy.
President Bush congratulated Colombian President Alvaro Uribe by phone. Uribe is slated to address the nation at 10 p.m. ET.
A senior State Department official said the United States played no role in the operation, though it was briefed on it ahead of time. The official called the operation "brilliant" and "a huge success," saying it involved a deception operation against the FARC.
According to Pentagon officials, Colombians had told the United States about the operation in the past few days. The U.S. approved the plans but had no part in them.
The United States is offering medical support to the three American contractors, including a medical evacuation back to America.
William Bronfield, a senior U.S. ambassador, confirmed that the U.S. was briefed about the operation. He is on his way to the Colombian airbase where the hostages were taken.
Contractors Stansell, Gonsalves and Howes have been held since February 13, 2003, when their single-engine plane crashed in the mountains south of Bogota. The Americans were working for Northrop Grumman Corp. as part of a U.S.-funded counternarcotics effort.
Two other men on the plane, American pilot Tommy Janis and a Colombian, were shot to death by FARC. A rescue plane searching for the men crashed six weeks later, killing its American pilot, Butch Oliver, and another American crew member.
Stansell, Gonsalves and Howes were last seen in a 2003 interview by a Colombian journalist who made his way into a FARC stronghold. The journalist's video was shown on CBS' "60 Minutes."
"To our country, we miss you, and we hope we return one day. We're alive and well," said Stansell, then 38, a systems analyst.
"We expect to get out of here one day. We can't say for sure," said Howes, then 50, a professional pilot. "But our main concern is the welfare of our families."
"I'm a proud American," said Gonsalves, then 31, also a systems analyst. "I look to you guys, and I ask for a diplomatic solution to get us home safe, please."