While sixteen UN barges were able to return to Nasir, the other eleven remain unaccounted for, and are believed to have been sunk or looted.[1][2] The WFP lost 735 tonnes of food aid in the attack and airlifted ten tonnes of aid to the area on 13 June.[3] The attack may have been made to prevent the food supplies reaching the Lou Nuer tribe which is alleged to have killed around 70 members of the Jikany Nuer tribe in attacks in May 2009.[4] It is feared that the Lou Nuer may be planning a retaliatory strike against the Jikany Nuer.[1]