Updated

A Colombian rebel leader is warning that criminal gangs are attempting to take over coca-growing regions being abandoned by the guerrillas to expand cultivation of the plant used to make cocaine.

The rebel leader known as Pastor Alape says the threats against communities in the northern Colombia could lead to a humanitarian crisis as scared farmers flee their homes.

He issued the warning at an event Friday to unveil the government's plan to wean thousands of families off the coca trade as part of a peace deal with the Revolutionary Armed Forces of Colombia.

Farmers who voluntarily substitute coca for legal crops will be eligible to receive monthly stipends as well as loans and technical assistance. The goal is to eradicate 50,000 hectares of coca in the first year.