More than 80 people were killed in the country’s northeast over the weekend following the government’s failed attempts to hold peace talks with the National Liberation Army, a Colombian official said.

The unusually deadly violence delivers a devastating blow to the “total peace” program of the country’s first leftist president, Gustavo Petro.

Clashes between armed groups in Colombia have led to some of the worst violence in the country in years. By Julie Turkewitz Reporting from Bogotá, Colombia At least 80 people are dead and more than 18,

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