By Betel Miarom N'DJAMENA, Feb 2 (Reuters) - Rampant insecurity along Chad's eastern border with Darfur is hampering efforts to aid hundreds of thousands of refugees, underlining the need for international peacekeepers, U.N. refugee agency UNHCR said on Friday. Rebels fighting to overthrow President Idriss Deby attacked the town of Adre on Thursday, the latest in a series of raids along a more than 400 km (250 mile) stretch of border where aid workers are sheltering displaced civilians from Chad and Darfur. "UNHCR is profoundly concerned about the unrelenting insecurity throughout eastern Chad and the precarious conditions in which literally hundreds of thousands of Sudanese refugees from Darfur and internally displaced Chadians fear for their lives," the U.N. agency said in a briefing note. There were varying reports of casualty figures from Thursday's attack on Adre -- which lies 170 km east of Abeche, the hub for international humanitarian operations -- but all suggested there had been heavy fighting. UNHCR said the clashes had killed around a dozen civilians and wounded at least 40. The rebels said 100 government soldiers and 13 of their own had been killed while the Chadian army said it had killed, wounded or arrested hundreds of rebels. "After violent clashes lasting more than three hours, (the rebels) were pushed back and chased several dozen kilometres into Sudan," said Kallimi Sougui, second deputy in charge of Chad's armed forces. "The security forces had close to 20 dead, around 30 injured and three vehicles damaged beyond use." Deby's government has accused Sudan of backing the rebels, including by allowing them to strike from Sudanese territory, as part of a campaign of regional destabilisation. Khartoum denies the charge. INSECURITY Chad's border region with Darfur, a desolate expanse of parched earth and dusty scrub, is home to 230,000 Sudanese refugees as well as 110,000 displaced Chadians and 46,000 refugees from Central African Republic to the south. Defying international pressure, Sudan is refusing to allow the deployment of U.N. peacekeepers in Darfur, where tens of thousands of people have been killed in conflict since 2003. The world body is also looking to send troops to Chad and Central African Republic to secure their borders with Darfur. A team sent by the U.N. Security Council is visiting the region to evaluate whether to deploy a mission. Aid groups say better security is vital for their work. UNHCR said Thursday's fighting alone forced all aid agencies in Farchana, about an hour's drive west of Adre, to remain on base with no access to some 62,000 Darfur refugees in the area. On the same day, armed men on horseback attacked four trucks carrying aid supplies more than 300 km (180 miles) to the south near the town of Am Timan. Instability to the north was also hampering aid efforts. Ethnic clashes around the town of Guereda, more than 100 km from Adre, had a "disastrous effect" on aid agencies' ability to help close to 30,000 refugees in camps there.
