Colombian president Gustavo Petro is warning that his nation's military will take offensive actions against the National Liberation Army after the rebels, known as the ELN, unleashed a wave of attacks in the country's northeast that left dozens of people killed and forced thousands to flee their homes.

More than 8,000 civilians fled the violence, with many seeking shelter in government facilities or hiding in the mountains.

The criminal war in northeast Colombia has escalated, as intense fighting between two Colombian guerrilla groups erupted in the Catatumbo region, a key cocaine production hub and criminal hotspot along the Venezuelan border.

Venezuela closed its borders and airspace to Colombia on Friday, the day President Nicolas Maduro is to be sworn in as the country's highest authority.

Nicolas Maduro is set to be inaugurated for a third term despite alleged vote fraud and international condemnation of his repressive tactics. His opponent was briefly detained at a protest on Thursday.

A fresh outbreak of guerrilla violence amid a faltering peace process in Colombia has left more than 80 people dead, including civilians,

Colombia vowed "war" against left-wing guerrillas Monday, as security forces rushed to contain a wave of violence that has killed more than 100 people and threatens to derail the country's

The death toll from attacks by ELN rebels in Colombia has risen to 60 in the country's restive Catatumbo region near the border with Venezuela, officials said Saturday. Around 60 people have been killed across Catatumbo,

Civilians caught in the crossfire as ELN guerillas target former members of a separate rebel group in the bloodiest violence in recent years A fresh outbreak of guerilla violence amid a faltering peace process in Colombia has left more than 80 people dead,

A fresh outbreak of guerrilla violence amid a faltering peace process in Colombia has left more than 80 people dead, including civilians, and displaced around 11,000 in just four days, officials reported on Sunday.

Former Colombian President Álvaro Uribe (2002-2010) called on Saturday for an international intervention in Venezuela, endorsed by the United Nations, to remove Chavista leader Nicolás Maduro from power after his inauguration on Friday.