Colombian military agents posing as members of FARC duped the rebel group into handing over former presidential candidate Ingrid Betancourt, three U.S. military contractors and 11 other hostages as part of a helicopter rescue, Colombian officials announced Wednesday.

Wearing military fatigues and a camouflage hat, Betancourt appeared healthy as she hugged her mother, Yolanda Pulecio, and her husband, Juan Carlos LeCompte, at a Bogota airport, six years after she was captured by the rebels.

"The military operation of the army of my country of Colombia was a perfect operation," she told reporters.

"This is a miracle. This is a miracle that I want to share with all of you," said Betancourt, who was kidnapped in 2002 at a roadside checkpoint while campaigning as a presidential candidate and had been in captivity ever since.

Earlier, Defence Minister Juan Manuel Santos said the hostages were freed without a shot being fired after military intelligence agents were able to infiltrate the ranks of the Revolutionary Armed Forces of Colombia (FARC).

The agents had led a local commander to believe they were going to take the hostages by helicopter to Alfonso Cano, the guerrillas' supreme leader. Instead, they disarmed the rebels and the helicopters took the hostages to a military base in Guaviare.

At the Bogota airport, the hostages walked up to a microphone one by one, identified themselves by name and rank, and thanked their rescuers. Some had been held for a dozen years, captured when rebels overran military outposts.

Betancourt recounted details of the rescue. She said the hostages had been told that they were going to be taken to speak with one of the commanders of the rebel group and that they would be transferred to be held somewhere else.

She said two white helicopters, which she didn't know were piloted by Colombian military agents, landed at a rallying point. People she believed to be members of FARC, wearing Argentine guerrilla Che Guevera T-shirts, exited the plane.

"The hostages were handcuffed and loaded onto the helicopter," she said.

"We were very indignant, very humiliated and very angry," Betancourt said.

But she said as soon as the helicopter doors closed and the helicopter started flying, she suddenly saw the local commander in charge of the hostages, alias Cesar, lying on the floor, naked and blindfolded.

"The chief of operations said: 'We are the national army and you are all free,' and the helicopter almost fell because we started jumping," Betancourt said. "We screamed, we cried, we hugged. We couldn't believe it."

Santos said Cesar and another rebel on board "were neutralized." He didn't elaborate, but said they were unhurt and would soon face justice. The other rebel captors retreated into the jungle and the army let them escape "in hopes that they will free the rest of the hostages," believed to number about 700, Santos said.

"What was carried out today by our public force is something truly blockbuster. It was almost like a movie," Santos said.

The plight of Betancourt, who holds French and Colombian citizenships, had taken on added urgency in recent months since another hostage, who spent months with her but was released in February, said Betancourt has hepatitis B and a tropical skin ailment.

Colombian news media have often reported that Betancourt is at death's door, citing unidentified peasants who said they had seen her.

The three U.S. contractors — Marc Gonsalves, Thomas Howes and Keith Stansell — were kidnapped in 2003 when their plane went down in southern Colombia. They were the longest-held American hostages in the world. They were flown to the United States and arrived at Lackland Air Force Base in San Antonio, Texas, shortly before midnight Wednesday.

Helicopters took them to the Brooke Army Medical Center in San Antonio, where they'll undergo tests and treatment.

U.S. Ambassador William Brownfield, who met with the men at a Colombian military base, said two of the three were suffering from the jungle malady leishmaniasis — a disease caused by protozoan parasites — and are "looking forward to modern medical treatment."

The other 11 hostages were Colombian soldiers and police officers.

The rebels had wanted to swap the hostages for all FARC rebels imprisoned in Colombia and the United States.

Betancourt's freedom follows high-profile international efforts to have her released. Earlier this year, French President Nicolas Sarkozy called for her release and sent a French medical team in hopes of supplying her with medical care.

FARC rejected Sarkozy's help, just as it rebuffed efforts by Venezuelan President Hugo Chavez to broker freedom for the hostages. Last month, Chavez gave up and called for FARC to release all of its hostages, saying "the guerrilla war is history" in Latin America.

Violence from Colombia's conflict has ebbed as Colombian President Alvaro Uribe's U.S.-backed military drove back FARC. The rebels have lost three top commanders this year. One was shot by his bodyguard, another was killed by Colombian armed forces and a third died of a heart attack. Government rewards have also been triggering desertions.

Uribe, whose father was killed by the FARC, also credits Chavez's apparent withdrawal of support from FARC for the rebels' setbacks, and the two presidents are expected to meet and discuss lowering tensions between their countries later this month in Caracas.

FARC was established in the 1960s as the military wing of the Colombian Communist Party and later became involved in the cocaine trade as a means of raising funds. The Colombian government estimates the rebel group has between 6,000 and 8,000 armed members and a military presence in 15 to 20 per cent of the country, particularly remote jungle and mountain areas.

Some estimates put the number of FARC fighters at as many as 18,000. The governments of Canada, the United States and the European Union all consider the organization a terrorist group.