FARC guerrillas Thursday accused President Juan Manuel Santos of escalating the war in Colombia even as his government engages in peace talks here.

The comments by the FARC's chief negotiator Ivan Marquez came in a week in which 26 rebels were reported killed in fighting in Colombia.

In Montevideo, Uruguay's President Jose Mujica said he would meet with Santos and the FARC delegation in Havana next week in an effort to speed up the peace talks.

Marquez accused Santos of having a "militaristic" approach that sees the use of force as "the key to achieving peace."

"One cannot distort reality believing that it is correct to escalate the war as if there were no talks, or that one can advance a dialogue pretending that the country is not suffering from the ravages of the confrontation," he told reporters here.

The FARC suffered heavy battlefield losses this week in a succession of Colombian military operations.

The Colombian army said 14 rebels were killed in an air and ground assault over the weekend on a rebel base in a rural region near the Venezuelan border.

On Tuesday, seven more guerrillas were killed in another army operation in the center of the country, and on Wednesday five died in another clash, according to army statements and sources.

Santos on Wednesday reiterated a vow to keep the pressure on the FARC even as he pursues a comprehensive peace at the Havana talks.

Mujica, a former leftist guerrilla himself, told the Uruguayan weekly Busqueda in an interview published Thursday that he would meet with the two sides next week in Havana after a Latin American summit.

"I am going to talk with President Juan Manuel Santos and the FARC," he said.

"I want to continue helping once again -- concretely, to accelerate the negotiating process," he said.

"Never before in the 50 years since this confrontation began, has peace been so close. This is a superior objective and deserves every support," he said.

Meanwhile the president of the Colombian Senate, during a visit to Washington Thursday, urged the US to continue providing aid to his country should an agreement be reached with FARC rivals.

"The same commitment" from US authorities "cannot disappear if the agreement with FARC is signed. It must be maintained intact, and not for the war but for peace," Juan Fernando Cristo said.

The United States currently funds Plan Colombia, a $9 billion anti-narcotics effort launched in 2000 that included a counter-insurgency element.

Talks between the Colombian government and FARC have been underway in Havana since November 2012, with preliminary agreements reached on two of five agenda points.

Negotiators are currently discussing how to deal with drug trafficking, an industry that has fueled the conflict.

Other issues that remain unresolved are compensation for victims of the conflict and the disarming of the rebel forces.

The FARC, formed in 1964, has an estimated 7,000 to 8,000 fighters under arms.

Mujica met in July with the rebel delegation to the talks during a visit to Havana, and met with Santos in September on the sidelines of the UN General Assembly in New York.