HONG KONG (AFP) – Hong Kong customs have seized HK$7.9 million (US$1 million) worth of illegal ivory hidden in luggage on a flight bound for Cambodia, officials said Tuesday.

The 790-kilogram (1,740-pound) cargo was found in 32 separate pieces of baggage en route from Angola.

Customs official Ng King-hong said that while large seizures of ivory were often made at Hong Kong’s container port, it was unusual for such a large consignment of tusks to be carried by air.

He said that the plane, which was in transit, would not normally have been subject to inspection by Hong Kong customs, but mechanical problems meant the baggage hold was unloaded and checked.

“They definitely wanted to skip Hong Kong. But unfortunately their flight broke down,” he said.

Fifteen Vietnamese smugglers aged from 20 to 54 were arrested, Ng said.

Hong Kong has one of the busiest container terminals and airports in the world and often sees seizures of banned products.

Tusk seizures have risen steadily since 2009, reaching a record 8,041 kilograms in 2013.

The government last month began destroying nearly 30 tonnes of ivory seized from smugglers in the world’s largest such operation, a major step in the fight against the illegal trade in elephant tusks.

Authorities plan to destroy the ivory stockpile over the course of a year.

A rise in the illegal trade in ivory has been fueled by demand in Asia and the Middle East, where elephant tusks are used in traditional medicine and to make ornaments.

Ivory is popular with Chinese collectors who see it as a valuable investment.

The international trade in elephant ivory, with rare exceptions, has been outlawed since 1989 after populations of the African giants dropped from millions in the mid-20th century to some 600,000 by the end of the 1980s.