Vietnamese customs officials said Wednesday they had found more than six tonnes of live protected pangolins inside a shipping container sent from Indonesia.
The rare creatures -- known as "scaly anteaters" for their unusual appearance and prized in China and Vietnam as an exotic meal -- were discovered last week during an inspection at the northern port of Hai Phong, a customs official told AFP, declining to provide further details.
The container, which was due to be shipped onwards to an undisclosed final destination, provided documents claiming it contained frozen fish, fins and fish bones, according to a report on the Vietnamese government's website.
Authorities have not specified what will happen to the pangolins.
Naomi Doak of wildlife trade monitoring network TRAFFIC estimated there were several hundred of the mammals in last week's haul and told AFP there were no rescue centres in Vietnam equipped to deal with such large numbers.
"They're hard to keep in captivity and feed, they only eat termites... my guess is they'll be killed and sold," she said.
Since the start of the year, more than 10 tonnes of pangolin -- both live and frozen -- have been confiscated at Hai Phong port, the government report said.
Authorities have also seized 1.2 tonnes of pangolin scales -- which are sought after in traditional Vietnamese and Chinese medicine as a remedy for allergies and to help male potency.
The small mammals are nearly entirely covered with scales, made of keratin -- the same protein that makes up human hair.
Pangolins sell for between eight to ten million dong ($380 - $480) per kilogram at restaurants in Vietnam, according to state media reports.
Trade in pangolins is banned by the Convention on International Trade in Endangered Species (CITES).