VILLAVICENCIO, Colombia - Venezuelan helicopter rescue teams waited at the edge of a Colombian wilderness on Saturday for the go-ahead from Marxist rebels to pick up three hostages held for years in secret jungle camps.

After weeks of promising to release two former politicians and the infant son born to one of them in captivity, the Revolutionary Armed Forces of Colombia, or FARC, has still not revealed their location.

Hugo Chavez, leftist firebrand president of neighbouring Venezuela, sent two helicopters into Colombia on Friday. But they remained grounded in the flat, hot and humid town of Villavicencio at the foot of the Andes mountains.

Although wary of Chavez and his goal of uniting South America under socialism, Colombia's conservative government let him fly Venezuelan aircraft painted with the colours of the Red Cross deep into its territory to collect the hostages.

"Once we get the coordinates from the FARC and the security guarantees to go to the area where the hostages are to be released, we'll be ready to start this humanitarian mission," said Yves Heller, spokesman for the International Committee of the Red Cross in Colombia.

Chavez is also trying to get the location from the rebels but said that poor communications from FARC jungle territory and bad weather were holding up the mission.

He had said earlier that Consuelo Gonzalez, Clara Rojas and her son Emmanuel could be free within hours of the arrival of the helicopters. Emmanuel, whose father is a guerrilla fighter, was born in a rebel camp and is thought to be 4 years old.

Villavicencio, in central Colombia, is a gateway to the country's southern jungles where the FARC controls wide areas used to produce the cocaine that funds its insurgency.

Chavez was told last month by Colombian President Alvaro Uribe to stay out of hostage negotiations with guerrilla leaders but he apparently continued secret talks and negotiated a deal to free the three captives.

On Friday the Venezuelan leader toured an air force base close to the Colombian border with foreign envoys, including former Argentine President Nestor Kirchner, who is to join the rescue party over the weekend.

U.S. filmmaker Oliver Stone, who is making a documentary about Latin America, was also with Chavez at the base and will travel to Colombia to observe the mission. He said he was a fan of Chavez and called him a "great man."

The release could help pave the way for freeing other rebel-held captives, including French-Colombian politician Ingrid Betancourt and three American anti-drug contractors, in exchange for jailed guerrillas.

It would also give Chavez a political victory just weeks after he lost a referendum vote that would have allowed him to run for reelection indefinitely and given him sweeping powers to accelerate his socialist revolution in Venezuela.

Chavez will not take part in the rescue party, but he plans to receive the freed hostages at a Venezuelan military base where relatives of the long-time captives will also gather.