Malaysian customs officials said Monday they have confiscated 18 rhino horns, weighing more than 51 kilograms, and valued at over $3 million. Customs said they found the horns in a crate Friday at the Kuala Lumpur International Airport cargo terminal after receiving an anonymous tip. The haul had been shipped from Mozambique via a Qatar Airways flight with false documentation, classifying the the horns as “obre de arte” — or work of art. Rhino horn global trade is banned under a United Nations convention. Malaysian officials say the case is under investigation and no suspects have been arrested. Rhino horns have been used for centuries in traditional Asian medicine, but they have not been proven to cure any illnesses. The wild rhino population at the start of the 20th century was 500,000, but has since dwindled to 29,000.