The president of Colombia called Saturday for accelerated peace negotiations with FARC guerrillas, just as eight rebels were killed in an escalating government offensive.

Juan Manuel Santos made the announcement amid a push by the Colombian army that began Thursday with a government air strike killing 26 guerrillas in the southwestern Cauca department.

Colombia's FARC guerrillas suspended their unilateral ceasefire Friday after a government air strike killed 26 rebels, plunging peace talks to end the five-decade conflict into a new crisis.

The December ceasefire announcement by the Revolutionary Armed Forces of Colombia (FARC) had raised hopes that the two-year-old peace negotiations were approaching a breakthrough. But tensions have spiraled since the rebels killed 11 soldiers in an ambush last month.

President Juan Manuel Santos on Tuesday said his defense minister was being reassigned and replaced, as the government wades through peace talks with leftist rebels.

The outgoing minister, Juan Carlos Pinzon, who has spent four years in the post, "will be taking over as ambassador in Washington," Santos said during an address.

A massive landslide tore through a ravine in northwest Colombia Monday before dawn, killing at least 61 people and injuring 37, authorities said.

Most residents were sleeping when the landslide hit the municipality of Salgar around 3:00 am, burying a large area in mud and debris.

Rescuers Friday said they had found six bodies in a collapsed, unlicensed gold mine on an indigenous reservation in a central Colombian town.

Another nine miners were believed to still be missing after the accident on Wednesday in the northwestern town of Riosucio, where authorities are carrying out an investigation of the mine.

Colombian rescuers said Friday they have found four bodies in a collapsed gold mine, as they searched for another 11 missing workers.

The unlicensed mine on an indigenous reservation in the central Colombian town of Riosucio collapsed on Wednesday. Authorities are investigating its owners.

Colombia's smaller insurgency, the National Liberation Army (ELN), has met with members of the main rebel force FARC, in Cuba, with the blessing of President Juan Manuel Santos, who is hoping it will lead to a second peace process.

The goal of the discussion, Santos said Monday, was "to make progress in our drive to put an end to more than 50 years of armed conflict" that has pitted the Marxist FARC and leftist ELN against the government and right-wing paramilitaries.

Four Colombian soldiers were killed and two others were wounded Sunday when their helicopter crashed in the central Uribe region, the military said. 

The UH-60L Black Hawk, U.S.-manufactured helicopter was ferrying supplies when the accident occurred at about 2:00 pm (1700 GMT), the army said in a statement.  

Two Colombian soldiers were killed in clashes with leftist ELN rebels, the country's second largest rebel group, the military said.

The army accused guerrillas from the National Liberation Army (ELN) of launching an attack in the northeastern town of Cubara near the Venezuelan border.

Colombian President Juan Manuel Santos ordered his government on Friday to step up an offensive against the leftist ELN guerrilla movement after the rebels showed off a soldier's severed leg.

Santos expressed disgust at reports that the National Liberation Army had placed an anti-personnel mine in a children's park in northwestern Colombia and that the explosion blew off both of the soldier's legs.