Two Venezuelan helicopters arrived Thursday in the Colombian town of San Jose del Guaviare, in a second attempt to secure the release of two hostages held by leftist rebels.

Irma Alvarez, spokeswoman for the International Committee of the Red Cross (ICRC) in Venezuela, told Venezuelan state television channel VTV that the operation had been launched.

The effort seeks to secure the freedom of former vice presidential candidate, 44-year-old Clara Rojas and former legislator Consuelo Gonzalez, 57.

The two women have been held by the Revolutionary Armed Forces of Colombia (FARC) for over six years years, along with hundreds of civilians and Colombian officials that have been held in some cases for more than 10 years.

Venezuelan President Hugo Chavez said Wednesday that the helicopters would fly to the Colombian province of Guaviare, and that he expected Rojas and Gonzalez to be free Thursday since FARC had given him the coordinates to find them.

The Colombian government authorized the mission and ordered the suspension of military operations in a large area of the southern province of Guaviare.

Colombian Defence Ministry sources said the helicopters were to refill their fuel tanks in San Jose del Guaviare and would then leave for the exact coordinates where FARC said they could find the hostages. Afterwards, the machines were expected to travel directly back to Venezuela.

Unlike a high-profile international effort to free these hostages that failed last week, the latest operation was being handled with great discretion by the Venezuelan government.

Venezuelan helicopters were flying under ICRC symbols, and each one was carrying a delegate of the Red Cross, which was taking part in the operation alongside the governments of Venezuela and Colombia.

Alvarez said that the Colombian government guaranteed the security of those involved in the effort.

The operation to free the two hostages, and Rojas' 3-year-old son Emmanuel, failed last week, apparently due to the fact that the boy had already been released to a child protection facility in 2005.

Gonzalez, then a legislator, was kidnapped on September 10, 2001. Rojas, in turn, was kidnapped on February 23, 2002 along with her party's presidential candidate Ingrid Betancourt, who holds dual French-Colombian citizenship and is the highest-profile hostage held by FARC.