CHRISTIAN Solidarity International (CSI) said on Tuesday it bought the freedom of 4_ 092 slaves in Sudan last week. The Zurich-based Protestant non-governmental organization said it had liberated 25053 slaves since 1995 using the controversial method at the price of 50 dollars per head paid to slave traders. Most had been abducted in southwestern Bahr el Ghazal Province in raids by Muslim tribes from the north as well as by northern pro-government armed forces, the CSI claimed. The UN Children’s Fund (UNICEF) has criticized the buying-back of slaves, saying the practice did not eradicate the cause of the problem: the civil war between southern rebels who are mainly animist or Christian and the ruling north, which is Arabised and mainly Muslim.