Rhino horns worth around $1 million were to be burned on Thursday at the San Diego Zoo in a bid to raise awareness about the endangered species decimated by poachers.
"This rhino horn burn sends the message to criminal networks and to rhino horn buyers that the United States will not tolerate illegal trade in rhino horn," Susie Ellis, the head of the International Rhino Foundation, said in a statement.
"The high demand for this commodity results in dire consequences for rhino species. Today's burn makes clear that confiscated horns should not be stockpiled, let alone traded."
The bonfire at the California zoo, which is home to 30 rhinos, comes as other zoos and private reserves around the world are increasingly holding similar high-profile events to shed light on the crisis facing rhinos.
Rhino horns can fetch thousands of dollars in East Asia due to their supposed medicinal qualities, fueling a boom in poaching and trafficking, particularly in Zimbabwe and South Africa.
Also believed to be an aphrodisiac, the horn is composed mainly of keratin, the same component as in human nails.
Kenya and Mozambique have already destroyed most of their rhino horn stockpile and conservationists are encouraging other governments to follow suit.
"With the increasing value of rhino horn, stockpiles present a high-value target for theft," Ellis said.
"In countries with limited resources to protect stockpiles, or with concerns about corruption, destroying horns can eliminate the risk of confiscated horn from entering the black market."
Officials at the San Diego Zoo said that if the current rate of poaching continues, rhinos could become extinct within 15 years.
The San Diego stockpile came from various seizures carried out by the US Fish and Wildlife Service, officials said.
Thursday's event, the first of its kind in the United States, comes ahead of World Rhino Day on September 22.
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