(Adds helicopter operation, crisis committee, UNHCR) By Moumine Ngarmbassa N'DJAMENA, Jan 31 (Reuters) - A Chadian rebel column advanced along the main road west towards the capital N'Djamena on Thursday but split up when confronted by the army and there was no threat to the city, officials said. Army helicopters bombarded the rebels who the government says crossed from Sudan earlier this week with backing from the neighbouring country's government, a military source said. President Idriss Deby, a French-trained former fighter pilot with a penchant for taking personal command on the battlefield, headed out to bolster government forces facing the rebels but later returned to N'Djamena, a presidency official said. "From the military point of view there is no threat to the capital ... the government is taking the necessary measures," said the official, who declined to be named. A government crisis committee was due to meet on Thursday evening and a Reuters witness said troops took up defensive positions on main roads into N'Djamena from the north and east. A security source in N'Djamena, declining to be named, said earlier a rebel column of 300 vehicles had passed through the town of Ati and halted 250 km (150 miles) east of N'Djamena where a Chadian army column had moved up to confront it. "There is a Chadian army column in front of them and there are other Chadian forces between them and the capital," he said. Opposition Web sites said the rebels had taken Ati. The rebels have waged a cat-and-mouse campaign for years against Deby, whose position is strengthened by a defence treaty with former colonial ruler France that includes support from French ground and air forces based in Chad. The most dramatic in a string of rebel offensives towards N'Djamena was repelled in April 2006 in fighting believed to have killed hundreds of people in the city. ESCALATION FEARS Rebel groups abandoned a ceasefire late last year, triggering pitched battles that both sides said killed hundreds. Chad and Sudan accuse each other of backing rebel groups in their respective territories, though each denies the charge. U.N. Secretary-General Ban Ki-moon, attending an African Union summit in Ethiopia, appealed to both countries for calm. "These developments are extremely dangerous and could lead to an escalation of the conflict in the region," he said. The European Union gave the final green light this week for a long delayed 3,700-strong peace force to deploy to east Chad in the coming weeks to protect 420,000 refugees and stem violence spilling over from Sudan's Darfur region. The U.N. refugee agency UNHCR withdrew most staff from the eastern town of Guereda on Thursday after five aid vehicles in the area were hijacked at gunpoint in just 72 hours. "We can not continue to perform our activities in favour of refugees," the UNHCR said in a statement. Chadian rebels have threatened to attack the European force if it interferes with their campaign against Deby, although European commanders have pledged not to take sides. In the dusty capital, schools emptied as teachers sent children back to their families. Nervousness swept the city. "The war has nothing to do with us civilians. I'm going home as a precaution, so I don't get killed in the street," said Mahamat Adoum, one of many civil servants heading home early. France closed its school in N'Djamena and told its citizens to limit movements. The U.S. embassy advised Americans to avoid travel to east Chad and limit non-essential movements. Britain advised citizens to leave Chad if possible. (Additional reporting by Pascal Fletcher in Dakar; Writing by Alistair Thomson; Editing by Pascal Fletcher and Ralph Gowling)
A displaced woman from the Luo tribe and her children secure their belongings inside a car at a makeshift camp set up for victims of ethnic clashes at the Thika police ...
