Venezuela's President Hugo Chavez has sent two helicopters into Colombia to start a sensitive mission to collect two women politicians and a young boy held hostage for years.
Speaking at a military base as the helicopters took off, Mr Chavez said the main rescue operation had been delayed because the rebels had not yet told him the precise location of their captives.
Although wary of Mr Chavez, Colombia's conservative government has agreed to let him fly aircraft deep into its territory to pick up the hostages, including a former vice presidential candidate and her young son, born in a rebel camp.
Mr Chavez had earlier said the captives could be free within hours, but a senior Red Cross official said the helicopters were unlikely to reach them until at least tomorrow.
The Venezuelan helicopters will first fly to the central Colombian town of Villavicencio and from there to a still unknown meeting point to pick up the captives.
Rough terrain and poor weather conditions could cause delays.
The hostages are Clara Rojas, captured during her 2002 vice presidential campaign, former lawmaker Consuelo Gonzalez, snatched the year before, and Rojas' son Emmanuel, who was fathered by one of her rebel captors about four years ago.
It is the first time in more than five years that the FARC has unilaterally released so-called political hostages.
Ms Rojas was the presidential campaign manager of French-Colombian politician Ingrid Betancourt when the two were abducted by FARC in February 2002. Ms Betancourt was not released.
They are among 45 hostages, including three from the US, whom the rebels want to exchange for some 500 FARC members held by the Colombian government. But the two sides have not agreed on conditions for that swap.
