Negotiators in Colombian peace talks here struggled Monday to clinch an agreement on how to reintegrate the FARC guerrilla group into the country's political life.

Government and rebel negotiators worked through the weekend in hopes of resolving the issue, but agreement remained elusive.

A FARC delegate, Rodrigo Granda, told reporters that the sides were still hard at work.

"We are advancing, and we have advanced a lot," he said.

After nearly a year of talks in Havana, negotiators have reached agreement on only one of five agenda points -- how to approach land reform and rural development issues that lie at the root of Latin America's longest insurgency.

The current negotiating session was supposed to have concluded last Thursday, but the sides decided to extend it through the weekend in hopes of wrapping up the second agenda point: the return to political life of the leftist guerrilla group.

The government delegation headed by former vice president Humberto de la Calle made no comments to the press here.

President Juan Manuel Santos, who is running for re-election in 2014, has urged the FARC to accelerate the talks, stressing the need for progress.

Santos faces a challenge from his predecessor Alvaro Uribe, who has been leading a charge from the right against the peace talks.

Four previous attempts at a negotiated settlement of the near 50-year-old insurgency failed.

The FARC, which is estimated to have about 8,000 fighters under arms, has been fighting the state since 1964.