KAMPALA, Uganda - Officials say a staggeringly large bust of smuggled ivory and pangolin scales in Uganda is worth $3.5 million.

Uganda Revenue Authority spokesman Vincent Seruma told reporters on Friday that the intercepted shipment contained more than three tons of elephant tusks and nearly a half-ton of pangolin scales.

He calls this one of Uganda's biggest such busts of illegal wildlife products.

Two Vietnamese nationals are being questioned in custody.

While the three freight containers 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.