The move is an effort to bring about the first peace talks between the government and rebels in six years.

Five townships are being turned over to the Revolutionary Armed Forces of Colombia (or FARC) for 90 days.

FARC rebels control large areas of Colombia

The rebels, whose stated goals are land redistribution and social reform, have been in conflict with the Colombian state for more than 30 years.

The zone covers an area of 42,000 square kilometres, roughly the size of Switzerland, and its northernmost border comes within 100 km of the capital.

Government forces have been withdrawing over the last three weeks, but civil authorities will remain in their posts with the authority to deputise citizens for law enforcement.

De facto government

The area has long been considered territory of the Revolutionary Armed Forces of Colombia, or FARC, who act as the de facto government in as much as a third of Colombia's national territory.

The FARC have been fighting against the state for 34 years and have grown to number 15,000.

Earlier this week, the FARC destroyed a police station in the jungle town of Mitu, killing at least 30 police, soldiers and civilians.

There is no ceasefire yet on the agenda, and it is not yet clear when actual talks will begin. When they do they will be the first direct negotiations in six years.

Right-wing paramilitaries have announced their intentions to sabotage the talks by entering the zone and killing residents who they suspect of sympathising with the guerrillas.