In total, 15 hostages were rescued, Defense Minister Juan Manuel Santos said at a news conference. All hostages were reported as being in reasonably good health.
Army commandos captured rebels patrolling a security ring around the hostages and were able to convince them to turn over the captives, Santos said. No one was killed in the rescue.
Betancourt was a former Columbian presidential candidate and she has been held for more than six years. The rescued Americans were three Defense Department contract workers who were captured in 2003 after their aircraft crashed in the jungle during a counternarcotics operation in the country.
Betancourt's plight especially drew international attention and put pressure on the Colombian government to work towards the release of the hostages.
An excerpt from a letter Betancourt was able to send her mother in 2007 was translated and published in the Washington Post, capturing her experiences.
"I am tired, tired of suffering, I have been - or tried to be - strong. These almost six years of captivity have shown me that I am not as resistant, nor as brave, intelligent or strong as I had believed," Betancourt wrote.
Betancourt's son, Lorenzo Delloye-Betancourt, said from France that the release is, "if true, the most beautiful news of my life," according to the Associated Press.
FARC has been holding about 40 high-profile hostages, attempting to exchange them for jailed rebels.
Sen. John McCain, the presumed Republican nominee in the U.S. presidential race is in the country and said one of his reasons for visiting is to highlight Colombia's military successes against FARC.
Colombia's military has gone after the leftist rebel group aggressively over the past year and defeated several of the more than 50 rebel fronts last year, reported the AP.
Once a 17,000-member force able to organize massive attacks, FARC now has about 9,000 fighters, according to Reuters. They lost three major leaders this year.
