VALLEDUPAR, Colombia (AP) _ Talks on 13 prison hostages stalled Monday, but inmates elsewhere took a guard captive and declared a hunger strike to protest poor jail conditions.

Negotiators said they're waiting for inmates in the Valledupar jail to respond to a government offer to discuss improving prison conditions if they release the hostages.

``They told me that they'll respond to us in writing. All we can do now is wait,'' said negotiator Jose Noe Rios, sent by President Ernesto Samper to Valledupar, 400 miles north of Bogota, to try to end the impasse.

All contact between negotiators and the inmates has been conducted by telephone. Sources close to the negotiations said the government is refusing to meet face-to-face with the inmates unless they release some of the hostages. The sources spoke on condition of anonymity.

About 10 inmates have demanded bulletproof vests, a cellular telephone and buses to take them to freedom, as well as foreign asylum.

The government has refused.

``(We hope) they understand that what they're asking for is an impossibility,'' Cesar state Gov. Mauricio Pimiento said.

The takeover began Thursday when prisoners overpowered guards and seized weapons. Three guards and a police officer were killed in the uprising.

Two hostages were released Friday. Since then, the hostage-takers have set up sand bunkers in a courtyard outside the offices where they are holding the remaining captives.

International Red Cross director Thierry Corbet said the hostages are in good condition and receiving food and medical attention.

``They're all being held together and doing well,'' he told The Associated Press on Monday from a cellular phone inside the jail.

The rest of the prison's 600 inmates apparently are not participating in the takeover.

Meanwhile, about 1,200 inmates on Monday took over a portion of the Modelo jail in Bucaramanga, 190 miles northeast of Bogota, to demand better conditions.

Some threw rocks while others threatened hunger strikes if officials don't improve conditions. The jail, built for 620 inmates, is operating at nearly double capacity.

On Sunday, about 20 prisoners stormed a section of the El Barne jail in Tunja and took a guard hostage. The prisoners released the guard on Monday after reaching an agreement with officials to improve conditions.

In the past three months, prisoners have rioted or created disturbances in at least 14 Colombian jails, demanding improved conditions and an end to corruption and overcrowding.