(Adds assassination of government official, rebel comment) By Jean-Magloire Issa BANGUI, June 5 (Reuters) - Up to 20,000 people fled their homes in Central African Republic last week when the army torched hundreds of houses after rebels assassinated a senior government official in the area, aid workers said on Tuesday. The northwest of the former French colony has seen waves of violence in the past two years in the form of rebel attacks and counter-raids by government troops who have burnt thousands of straw-thatched mud houses trying to flush out insurgents. Humanitarian agencies reckon some 290,000 civilians from northern Central African Republic have been forcibly displaced in the past 18 months, including 78,000 who have crossed into neighbouring Chad, Cameroon and Sudan. Government sources said rebel fighters had attacked the town of Ngaoundaye, not far from the borders of Cameroon and Chad, on May 29, killing Noel Gai, sub-prefect for the surrounding area. Laurent Djim Woei Bebiti, a spokesman for the rebel Popular Army for the Restoration of the Republic and Democracy (APRD), told Reuters by satellite telephone that the group's fighters had "executed" Gai because he had invited Chadian troops across the border to help put down an APRD offensive in April. Last week's violence sent nearly 300 people fleeing across the border into Chad, including men with bullet wounds, U.N. refugee agency UNHCR said. "After initial rebel attacks on Ngaoundaye, government forces reportedly entered the town and burned 540 houses, forcing most of the estimated 3,000 to 4,000 inhabitants to flee their homes," the Geneva-based agency said in a briefing note. INACCESSIBLE "The area remains insecure and inaccessible to U.N. staff. It is difficult to get precise information but initial reports from humanitarian workers on the ground indicate that up to 20,000 people might be displaced in the area," it said. UNHCR gave no indication of deaths, but a military source in the area told Reuters at least five villagers had been killed during the anti-rebel operations by the army, which included members of President Francois Bozize's guard. A relief worker said government forces had arrived from the larger towns of Paoua and Bocaranga after Gai's death and burned almost all the houses in Ngaoundaye. Government officials have acknowledged previous raids by the army and the burning of civilians' houses by soldiers trying to quell the rebellion. Central African Republic has been drawn into a regional vortex of violence spreading west from Sudan's Darfur region, where Sudanese government forces and allied militias have fought rebels for four years in what Washington has branded genocide -- a charge Khartoum rejects. Violence has forced hundreds of thousands of civilians from Darfur, Chad and Central African Republic to flee to live rough in the bush or escape across international borders for safety. Adding to the strife in northern Central African Republic, rebel forces crossed the border from Sudan late last year and seized a swathe of territory around the northeastern town of Birao before being fought off by pro-government forces backed by French fighter planes and special forces. (Additional reporting by Alistair Thomson in Dakar)
