Peace Commissioner Luis Carlos Restrepo said that if some captives were liberated, it could begin the process of exchanging rebels for hostages.The offer, backed by the president, comes amid reports that Betancourt, a French-Colombian citizen, is ill. She is said to have hepatitis B and a tropical skin disease.Colombia’s human rights ombudsman Wolmar Perez said earlier that Betancourt’s health was “very, very delicate”.He said the government had received reports that showed the former senator had been taken to a public clinic in the jungle of southern Colombia in February.Announcing the “humanitarian” offer, Restrepo told a news conference: “The legal basis for a humanitarian exchange has been established and we have reduced the requirements as much as possible.”The government has joined the national and international cry that the life of Ingrid Betancourt be saved. We cannot run risks in this case and there is no more time to wait.”But Restrepo said that in return for their release jailed rebels would have to promise not to return to the ranks of Farc, which has been fighting the Colombian state for five decades.Ingrid Betancourt (46) is the most high-profile of the scores of hostages held in the jungle by the Revolutionary Armed Forces of Colombia, or Farc. She was abducted during the presidential campaign in 2002.She was pictured in a recent video, looking thin and frail.There has been an international campaign for her release, with the presidents of France and Venezuela among those calling for her release.Venezuela’s President Hugo Chávez played a key role in negotiating the release of 10 hostages in January and February.But such developments ended when a Colombian strike on a rebel camp across the border in Ecuador angered the government in Quito and its Venezuelan allies.