in northern Bolivar province for the hostages, President Andres Pastrana issued a strongly worded communique accusing the National Liberation Army (ELN) of "terrorist practices" and of violating "elementary rules of international humanitarian law." The Dutch-made Fokker 50 aircraft, operated by Avianca airlines, took off from the northwest city of Bucaramanga on Monday morning but minutes later was forced to land on a clandestine airstrip where the passengers and crew were abducted. Earlier in the day, military sources said hundreds of soldiers and police, including counterinsurgency specialists and crack commandos, were involved in the air and ground search in the area where the plane set down Monday. But by nightfall, there was no word on the whereabouts of the guerrillas or their captives, thought to include an American, an Italian, at least one congressman and two top executives of a state-run natural gas distribution company. The plane landed close to an area that the ELN has demanded state security forces vacate as a condition to peace talks aimed at ending the country`s long-running conflict. Pastrana has, however, refused to demilitarize the area, prompting the ELN to break off all meetings with government officials and to warn it may step up attacks. The president`s statement called for the immediate release of the hostages and urged the ELN to look for a peaceful settlement in the three-decade-old war that has claimed more than 35,000 lives in the last 10 years alone. An internal police document obtained by Reuters had said the ELN carried out the hijacking in conjunction with fighters from the larger Revolutionary Armed Forces of Colombia (FARC). But Pastrana`s statement, read by his peace commissioner Victor Ricardo, made no reference to the FARC which is due to restart peace talks with the government next week after a three month suspension. Sources close to the rebels said the plane`s seizure, and military reports of attacks around the country overnight, may signal the start of a fresh nationwide offensive aimed at strengthening the guerrillas` hand at the peace table. As troops searched for the hostages, fierce fighting between army units and FARC insurgents raged in the northeast banana-growing region of Uraba. Regional FARC leaders said they had attacked a group of 43 soldiers, killing at least 25. The army, meanwhile, said 12 soldiers had been killed, two others were injured and 13 were missing. It also said it had killed about 20 guerrillas.