Colombia offered a limited suspension of military and police operations if the country's biggest rebel group agrees to negotiate an exchange of prisoners, including three Americans held in jungle camps.

It was seen as a softening of the position of President Alvaro Uribe, a Washington ally elected in 2002 on promises that he would crush Colombia's Marxist insurgency.

The government said it would suspend arrest orders pertaining to negotiators representing the Revolutionary Armed Forces of Colombia during a 10-day meeting to be held in the town of Pradera in the western province of Valle de Cauca.

It also offered to suspend military and police operations "in the place of the meeting" during the talks.

"It is a big step for Uribe to offer a suspension of military operations. Until now he has resisted any concession like this to the guerrillas," said Mauricio Romero, political analyst at Bogota's Rosario University.

The rebel group issued no immediate response to the offer.

Uribe has been criticized by European governments and human rights groups for engaging in peace talks with the country's violent right wing paramilitaries while maintaining what they call an inflexible stance concerning the rebels.

Uribe wants the 41-year-old rebel group, known by its Spanish initials FARC, to release about 70 hostages held in secret jungle camps. The hostages include former presidential candidate Ingrid Betancourt -- a dual French-Colombian national -- and three U.S. Defense Department contractors captured when their plane crashed on a narcotics reconnaissance mission in 2003.

In exchange the government is offering to release FARC members held in government jails.

"The government will guarantee security conditions for the meeting ... and will ask judicial authorities to suspend arrest orders," it said in a statement.

Polls show a prisoner exchange would be popular. Uribe wants to run for re-election next year.

But chances of a deal have looked remote, with the rebels refusing to promise Uribe that if he releases any of the thousands of their comrades held in jail, they would not return to insurgent ranks.

Early last month the FARC, which is listed as a terrorist organization by the United States and the European Union, said it would negotiate only if troops completely pulled out of two mountain towns in Valle del Cauca.

Uribe was a harsh critic of the previous administration's failed peace talks, which took place in a zone abandoned by state security forces.

Thousands die every year in Colombia's decades-old guerrilla war, fueled by the country's 60-percent poverty rate and partially funded by money from drug trafficking.