Armed men killed 10 southern Sudanese in an ambush, a southern minister said on the third day of a referendum on independence for the south, but voters have defied gloomy predictions and turned out in huge numbers. The attack on a convoy of people returning to the south for the referendum was the latest reported violent incident to mar the week-long vote, which is expected to see the south emerge as a new nation. Vote organisers told Reuters a big turnout so far was almost guaranteed to reach the 60 percent of voters needed to make the poll valid. "A number of returnees were ambushed yesterday by a group of armed Misseriya. They ambushed 10 buses and seven trailers loaded with the belongings with these IDPs (internally displaced persons) coming from the north," southern internal affairs minister Gier Chouang Aloung told reporters on Tuesday. Aloung said the attack had happened on the northern side of the border between the northern state of Southern Kordofan and the southern state of Northern Bahr al-Ghazal and local authorities had told him 10 died in the attack.