Let me see my father again before I die, boy with cancer asks Colombian rebels

Andres Felipe Perez, a 12- year-old Colombian cancer patient with weeks to live, is begging to see his father for Christmas. But the Revolutionary Armed Forces of Colombia (Farc) has refused to release the policeman, who was kidnapped nearly two years ago by the leftist guerrillas.

Hostages are often permitted to watch television or listen to radio, but no one seems to know whether Jose Norberto Perez is aware of his son's critical condition.

The plight of the boy, bald and gaunt from chemotherapy, has left war-hardened Colombians aghast. Some 2,000 people have come forward, ranging from schoolchildren to senior politicians, each offering to swap places with the captive father so he might see his terminally-ill son and donate a kidney in a last effort to save him. One teenager reportedly marched to the edge of the Farc's autonomous safe haven in the southern jungle to offer himself. The vice-president and minister of defence, Gustavo Bell, has also volunteered to be a stand-in.

Manuel "Sureshot" Marulanda, Farc's commander-in-chief, demanded that the boy be examined by rebel physicians to confirm the grim diagnosis. But doctors say young Andres is in too much pain for an extended journey, and he is expected to leave hospital and spend his final days in his maternal grandparents' home. Surgeons removed a large tumour from his right lung and he needs an oxygen cylinder to breathe.

Appeals by the Roman Catholic church for the Farc to drop their political hard line and show compassion for a child's suffering have been ignored.

The Bogota government rejected Farc's proposed prisoner swap at the weekend and refused to capitulate to their demands to release a jailed rebel, Ignacio Gonzales Perdomo, who, the guerrilla army claims, is also "grievously ill". Eduardo Cifuentes, Colombia's senior human rights official, said: "By demanding payback for a simple humanitarian gesture, the Farc is extorting an entire country."

In July, the guerrillas released 363 police and security troops from a notorious internment camp in exchange for 11 rebels, but continue to hold about 50 hostages, including Andres's father.

An estimated 3,000 Colombians are abducted every year by leftist guerrillas, who use ransom payments to purchase weapons and ammunition to continue their 37-year Marxist insurgency. At least 40,000 lives have been lost in combat over the past decade alone.

But the Farc, the country's biggest guerrilla force, is changing tactics. One commander said: "We have to grab people from the Senate, from Congress, judges and ministers, and we'll see how they squeal."

On Sunday, Bogota college students led 4,000 Colombians in a mass protest march. In Bogota's main park, an enormous blank billboard was erected where the public can scrawl irate messages or appeals to the Farc guerrillas. One said: "If the revolution means the death of pity and solidarity, what's the point of being a revolutionary?"