In his first speech since King Charles III gave him his new title last month, the Prince of Wales said the illegal wildlife trade can be defeated after a man was jailed for conspiring to traffic millions of dollars' worth of rhinoceros horns and elephant ivory.
Prince William called US district judge Gregory H Woods's sentencing of Moazu Kromah to more than five years in prison a “significant victory”.
Kromah was convicted of conspiring to traffic rhino horns and elephant ivory in a crime that involved the deaths of about 135 animals.
In July, Prince William paid tribute to the “committed and brave” ranger Anton Mzimba who was reportedly shot and killed outside his home in South Africa.
The prince called for those responsible for the conservationist's death to be “swiftly brought to justice”.
“There's a front line and that's the worrying thing,” the prince said. “There's a war going on and everyone doesn't really see it.”
Prince William added that the most recent statistic he had heard was that, in the past 10 years, more than 1,000 rangers have been killed in Africa protecting local wildlife and communities.
“It's terrifying,” he said. “It really is.”
Before his speech, he met Altin Gysman of the Southern African Wildlife College, who was a friend and colleague of Mzimba. The prince called Mzimba's death a “shocking moment” and praised rangers for their work protecting endangered animals.
The heir to the British throne was speaking at the United for Wildlife global conference at the Science Museum in London.
United for Wildlife was created by Prince William and The Royal Foundation charity in 2014 to protect endangered species from the illegal wildlife trade.
Its stated mission is “to foster cross-sector collaboration to make it impossible for traffickers to transport, finance or profit from illegal wildlife products”.
The prince has long campaigned against the illegal wildlife trade, previously calling for a commitment to end the “abhorrent crime”.
This week's conference is being hosted by Royal Foundation chairman Lord Hague and will bring together more than 300 global leaders from law enforcement agencies, conservation organisations and private sector companies that are part of United for Wildlife.
The event will include speakers announcing policies and unveiling partnerships in a bid to end the illegal wildlife trade, which is worth up to $20 billion per year and is associated with violent crime, corruption and other forms of trafficking.