A huge shipment containing 3.5 tons of elephant ivory was seized in Singapore en route to Vietnam on Thursday, authorities said.
Officials said the shipment had arrived from Nigeria, the Strait Times reported.
An inspection uncovered ivory that could have fetched around $2.5 million on the black market, the report said.
Elephants are a protected species under the Convention on International Trade in Endangered Species of Wild Fauna and Flora, of which both Singapore and Vietnam are signatories.
Vietnam outlawed the ivory trade in 1992 but the country remains a top market for ivory products prized locally for decorative purposes or in traditional medicine, despite having no proven medicinal qualities.
Weak law enforcement in the country has allowed a black market to flourish, and Vietnam is also a regular transit point for tusks trafficked from Africa destined for other parts of Asia, mainly China.
The country reported dozens of seizures last year, including one case in which three tons of ivory were found in the central province of Thanh Hoa in July.