Vietnamese authorities have destroyed more than 2 tons of confiscated elephant ivory and rhino horns, sending a message ahead of an international conference that they want the wildlife trade stopped.

The horns—estimated to be worth more than $7 million on the black market—came from some 330 African elephants and 23 rhinos that were slaughtered by poachers to meet the demand for ivory used as jewelry and in the misguided belief they can cure cancer.

The horns were crushed and then burned Saturday on the outskirts of Hanoi, with Vietnam joining 20 other nations in destroying seized wildlife products.

An international conference on the will be held in Hanoi next week.