The tusks, weighing 505 kg, were found along with 324 kg of pangolin scales in an air shipment on its way to Laos on Dec. 12, Singapore Customs and the agriculture and veterinary agency said in a joint statement.

The boxes were labelled as synthetic wigs and had come from Nigeria, the authorities said, adding that the shipment had an estimated value of S$1.3 million ($920,000).

Trade in ivory and the endangered pangolin, a mammal that looks like an anteater, is restricted under the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), but demand remains strong in parts of Asia, where these animal products are prized for their supposed medicinal value.

The seizure was the fifth-largest seizure made in Singapore since 2002, and follows the seizure of 3.7 tonnes of illegal ivory earlier this year in a shipping container that listed the contents as tea leaves from Kenya.

Illegal trade in wildlife products covered by CITES carries a penalty of up to two years jail or a fine of up to S$500,000. ($1 = 1.4165 Singapore dollars)