BRUSSELS — Two prison guards have been taken hostage at a penitentiary outside the Swedish city of Eskilstuna by two men convicted of serious crimes.

Earlier on Wednesday the convicts broke into a guard room in Hallby Prison armed with razor blades and barricaded themselves in with the hostages.

According to media reports, the pair are aged 24 and 30 and have demanded a helicopter for their use.

Swedish broadcaster SVT said the inmates had also agreed to release one of their hostages in exchange for 20 kebab pizzas, one for everyone on their ward.

Pictures were later published by local media showing pizzas being loaded into a car in Hallby, said to be bound for the prison.

The Swedish Prison and Probation Service said it was a "very dangerous situation" The Swedish news agency TT said the pair were convicted murderers.

"The inmates have been convicted of serious crime," the probation service's acting security chief Jorgen From Nordin told TT. "The Swedish Prison and Probation Service's negotiators, task force and police are on site and the situation is frozen."