Authorities on Tuesday seized 24 tonnes of elephant tusks hidden in two containers at Malaysia’s main port of Klang.

Malaysian customs discovered the 1,500 tusks within pieces of timber in containers believed to have been transferred from one ship to another in Spain, headed for China, state customs director Azis Yaacub told AFP.

“The two containers were found to have been filled with sawn timber. Inside the wood there were secret compartments that were filled with elephant tusks,” he said.

The haul, worth 60 million ringgit or almost $20 million, was the largest officials have ever seized.

International trade in elephant ivory was banned in 1990, with rare exceptions such as auctions of tusks from elephants that have died naturally. The population of African elephants have now plunged to 470,000 from almost five million in the first part of the century as ivory trade increased mainly because of demand in China where tusks are used in traditional medicine.

Malaysia has been named as a major hub for illicit wildlife trade, according to TRAFFIC, a wildlife trade-monitoring network.