BOGOTA (Reuters) -At least 20 Colombian fighters from rival rebel factions were killed in weekend clashes over control of a strategic jungle area for drug trafficking, military sources and the human rights ombudsman office reported on Monday.

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,

Colombia vowed "war" against left-wing guerrillas Monday, declaring a state of emergency and deploying thousands of soldiers to contain a wave of violence.