Colombian troops killed 14 FARC guerrillas in fighting over the weekend, as the military pressed an offensive ahead of a resumption of peace talks in Havana.

The fighting was part of a "sustained and continuous operation" against the FARC in northwestern Colombia, General Juan Pablo Rodriguez, head of the armed forces, told reporters on Monday.

In a Twitter message, President Juan Manuel Santos congratulated the military on the success of its operation.

The spike in military activity comes with government and rebel negotiators poised to resume peace talks Tuesday after a pause of more than a month for national elections.

Despite his re-election on June 15 on a peace platform, Santos has vowed to keep the military pressure on the FARC until a comprehensive peace agreement is reached.

The FARC, Colombia's largest guerrilla group, has been holding peace talks with the government since November 2012, but there has been no ceasefire in Latin America's oldest armed conflict.

The weekend action "shows that the military forces and police are on the offensive," Rodriguez said.