President Alvaro Uribe on Friday ordered the Colombian military to rescue former presidential candidate Ingrid Betancourt and three US contractors that leftist rebels are holding hostage.

Betancourt was abducted by rebels with the Revolutionary Armed Forces of Colombia (FARC) in February 2002. The three Americans were captured one year later when rebels shot down the plane they were operating in anti-drug operations.

The rebels want to swap 56 of their blue-chip hostages -- including military officers, senators, provincial governors and mayors -- for 500 jailed FARC members.

"Generals, we are going to rescue Ingrid Betancourt and the three Americans," Uribe said, speaking at a ceremony in which the new head of the national police took office.

"We are not playing around with those FARC bandits, there will be no demilitarized zones," Uribe said. "We will never have peace with the FARC."

Uribe's predecessor, Andres Pastrana, created a Switzerland-sized demilitarized zone in southern Colombia hoping to negotiate an end of to the FARC's four decades-long insurgency. Talks collapsed, and soldiers moved into the zone in 2002.

In 2005, France, Switzerland and Spain revived the idea of a demilitarized zone to serve as a site for a hostages-for-prisoners swap.

Uribe's announcement came one day after a police officer who fled the FARC after nine years of captivity told reporters that Betancourt, 45, a Franco-Colombian citizen, had tried to escape five times.

John Frank Pinchao Blanco broke free from a FARC rebel camp where nearly 60 other hostages are being held, including the Americans and Betancourt.

He said Betancourt was "severely punished" for her escape attempts.

Betancourt's family, who are critical of the Uribe administration, earlier said they opposed the president's plan to liberate the hostages by force, saying they feared a bloodbath.

Separately Foreign Minister Fernando Araujo, a FARC hostage for five years, publicly urged the hostages to try to look for opportunities to escape.