BOGOTA, Colombia (AP) — Colombia on Thursday suspended permits for rebel leaders negotiating a peace deal in Cuba to visit guerrilla camps after top commanders showed up with weapons in a town's main plaza in what the government said was a flagrant violation of the ground rules for such missions.

The announcement by top government negotiator Humberto de la Calle followed the surprise appearance in photos and video footage of leaders of the Revolutionary Armed Forces of Colombia interacting with townspeople with heavily armed guerrillas standing by.

The incident took place along Colombia's border with Venezuela, De la Calle said without providing more details. Among those present was the rebel leader known by his alias Ivan Marquez, who is head of the FARC negotiating team.

"For the government, a fundamental rule of this agreement is that there will be no politics with arms," De la Calle said in a statement from the presidential palace. "This is an unacceptable violation."

The rebel group issued no immediate comment on the government's action.

As part of peace process, the government has facilitated travel by FARC commanders back and forth from Cuba to rally troops. But De la Calle said they are not allowed to carry weapons or engage with civilians while on such missions.

In addition to suspending permits for future meetings, De la Calle demanded Norway and Cuba, the peace talks' sponsors, work with the International Committee of the Red Cross to make sure Marquez and the other commanders immediately return to Cuba.

Pictures circulated showing rebel commanders holding what looked like a political event, complete with a stage, loudspeakers and flyers for distribution.

The images provoked outrage among conservative critics of the peace negotiations and many regular Colombians who worry the FARC will never hand over their weapons despite recent advances in the talks.

Former President Alvaro Uribe, who is now a senator and a fierce critic of the peace process, said on Twitter that the pictures show the rebels are engaging in politics while still armed.

Sen. Armando Benedetti, a fervent proponent of the peace effort, defended the commanders, saying they visited the town in the spirit of peace to talk to residents.

The setback comes as the more than 3-year-old talks had recently accelerated in the hopes of meeting a March 23 target for signing a final deal.

President Juan Manuel Santos traveled to Havana last year and shook hands with the rebel's top military commander to seal an agreement on what until then had appeared to be the peace talks' biggest obstacle: an agreement on how to judge and punish rebels, as well as state actors, behind scores of atrocities in the half-century conflict.