A staggeringly large bust of smuggled ivory and pangolin scales in Uganda is worth $US3.5 million ($A4.8m), officials say. Uganda Revenue Authority spokesman Vincent Seruma says the intercepted shipment contained more than three tonnes of elephant tusks and nearly half a tonne of pangolin scales. Seruma called it one of Uganda's biggest such busts of illegal wildlife products. Two Vietnamese nationals are being questioned in custody. While the three freight containers that were seized came from neighbouring South Sudan, Ugandan officials believe the ivory and pangolin scales came from neighbouring Congo and are speaking with authorities there. The contraband had been concealed inside pieces of timber and was detected with the help of a scanner. Africa's elephants and pangolins, or scaly anteaters, are under threat from poachers and are in demand in some Asian countries. Australian Associated Press