KUALA LUMPUR, Malaysia (AP) — Malaysian authorities said Monday that they have seized 18 rhino horns believed to have been smuggled into the country from Mozambique.

Airport customs director Hamzah Sundang said the horns were flown from Mozambique and transited in Doha before arriving at Kuala Lumpur's airport on Friday. He said the horns, which weighed 51.4 kilograms (113 pounds) and were worth 13.6 million ringgit ($3.1 million), were declared as art objects in a forged air bill with a fake final destination.

Hamzah said that custom officials made the seizure at the airport cargo warehouse based on a tip and that no arrests were made. The case is being investigated for smuggling of prohibited goods.

Rhino horns are believed to have medicinal properties and are in high demand in Asia.

In a report last year, the wildlife trade monitoring network TRAFFIC said Malaysia was a world transit hub for the flow of tons of illicit elephant ivory between Africa and Asia. It said seizures also linked Malaysia to Kenya and Uganda in the trafficking of 23 rhino horns from August 2010 to December 2013.

Conservationists say there are only around 30,000 rhinos left worldwide, compared to about half a million decades ago. All five remaining rhino species are threatened species, with three out of the five listed as critically endangered.