Colombia vows 'war' against left-wing guerrillas as violence kills more than 100

Colombia vowed "war" against left-wing guerrillas Monday, declaring a state of emergency and deploying thousands of soldiers to contain violence that killed at least 100 people and threatens to scupper the country's fragile peace process.

In just five days, bloodshed has been reported across three Colombian departments -- from the remote Amazon jungle in the south to the mountainous northeastern border with Venezuela, where fighting has displaced almost 20,000 people.

Analysts say the spasm of violence was caused by a turf war between rival militias, who see the faltering peace process as a threat to their unity and their profits from the ultra-lucrative cocaine trade.

President Gustavo Petro, who until now had staked his political fortunes on a strategy of de-escalation and dialogue, signaled the crisis would cause a shift in policy.

On Monday, he issued a defiant warning to leaders of the National Liberation Army, or ELN, which is said to have been behind border region attacks on rival leftist groups, killing 80 people.