FARC rebels resumed peace talks with the Colombian government here Monday after a brief pause in reaction to a proposal that any agreement be put to a national referendum.

The Revolutionary Armed Forces of Colombia criticized President Juan Manuel Santos' proposal as a "flagrant violation" of agreements that led to the peace talks, but decided to resume discussions anyway.

FARC guerrillas killed 13 soldiers in an attack on a Colombian army patrol shortly after officials announced talks with the leftist rebels would resume Monday.

"We regret to inform you that as the result of a FARC terrorist attack, two sergeants and 11 soldiers were killed," the Colombian army leadership said in a statement Saturday.

Colombia's FARC guerrilla group said Friday it was putting peace talks on pause to examine a government proposal that any peace agreement must be submitted to a national referendum.

President Juan Manuel Santos said in Bogota that the FARC's decision to take time out to study the referendum proposal was "legitimate and valid."

Colombia on Wednesday more than doubled the size of a huge nature reserve as it fights to protect the Amazon from deforestation.

Environment Minister Juan Gabriel Uribe said deforestation of the Colombian Amazon is a worrisome problem, mainly because of land being cleared for growing coca leaves, logging, illegal mining and agriculture.

A 6.5 magnitude earthquake rattled northwestern Colombia Tuesday but there were no immediate reports of casualties or damage, authorities said.

The Seismological Network of Colombia said the quake struck at 10:43 am (1543 GMT) in the Pacific Ocean, 99 kilometers (60 miles) from the town of Nuqui in the department of Antioquia.

U.S. Secretary of State John Kerry urged Palestinians "not to react adversely" Monday to Israel's announcement of more settlement building, and stressed the importance of "getting to the table quickly."

The chief U.S. diplomat, visiting Colombia, said that Israel's announcement on new settlements was "to some degree expected" and he did not think it would become a "speed bump" to a recently relaunched peace process.

Colombia's president praised the army Saturday for killing a regional commander of the leftist rebel group FARC, even as both sides are holding peace talks in Havana.

Jesus Antonio Plata Rios, whose nickname was Zeplin, died Friday in an army attack in southwest Colombia, the defense ministry said.

Colombian police said Tuesday they intercepted a vehicle loaded with explosives in Bogota, foiling an attack by FARC guerrillas.

Two men accused of belonging to a FARC cell were arrested Monday night as they drove through the city with 25 kilograms of an explosive mixture of ammonium nitrate and fuel oil, police said.

Colombian President Juan Manuel Santos said Thursday he is willing to start peace talks with the leftist ELN rebels as soon as they release a Canadian hostage, held since January.

The ELN, or the National Liberation Army, has on numerous occasions expressed interest in negotiating with the government.

Colombia will not agree to a ceasefire with FARC rebels, the country's president stressed Saturday ahead of a resumption of peace talks.

Juan Manuel Santos said that, since the start of the talks last year, his government has put Latin America's longest-fighting insurgency on notice that there would be no truce until a five-point agenda had been agreed.