HAVANA (AP) — Negotiators from the Colombian government and the country's biggest guerrilla army resumed peace talks in Havana on Monday after the rebels briefly walked away from the table last week.

The two sides are still in disagreement on the issue behind the time-out: whether to call an assembly to rewrite the constitution if a peace deal is reached.

The Revolutionary Armed Forces of Colombia, or FARC, says a constitutional assembly is necessary. President Juan Manuel Santos insists that that will not happen, and is proposing a national referendum on an eventual peace pact instead.

Still, the FARC said Monday that it would not abandon negotiations.

"Despite the circumstances the FARC will remain at the table, faithful to the commitment to seek peace for Colombia through all means," the rebels said in a statement read to journalists by negotiator Ivan Marquez, whose legal name is Luciano Marin Arango.

The FARC announced Friday that it would take a pause from the talks to study Santos' referendum proposal, and said Monday that the issue must still be negotiated.

"Let it be clear once and for all that there will be no submission by the FARC to any legal framework with unilateral designs," Marquez said.

The FARC, formed in the 1960s, is the oldest active guerrilla army in the Americas.

Peace talks have been taking place in Cuba since last year.