• Twenty-one rhino horns worth an estimated $5m have been seized in Thailand after being found in luggage sent from Ethiopia in the biggest such haul in years. • The seizure comes days after 300kg of elephant ivory was also impounded in the country. • Thailand is seen as a transit point for the illegal trafficking of wildlife. • Several species of rhino are at critical risk of extinction, conservationists say. • The horns arrived at Bangkok's international airport where two Thai women who had travelled from Vietnam and Cambodia came to collect them. • According to Thai police, they ran off when the luggage was subjected to a random check. • Officials describe the incident as an elaborate smuggling effort which involved several other people inside Thailand and abroad. • Wildlife campaigners believe the rhinos were probably killed to order in southern Africa, a BBC correspondent in Bangkok says. • Activists say that despite improvements in Thailand's anti-smuggling efforts, its main airport remains a popular hub for wildlife smuggling in Asia. • Some 29,000 rhinos are left in the wild today compared to 500,000 at the beginning of the 20th Century, according to the International Rhino Foundation. • Earlier this month, poachers shot a rhino dead and hacked off its horn at a zoo in France in what is believed to be the first such incident in Europe. • Last month poachers stormed an animal orphanage in South Africa and killed two rhinos for their horns after taking staff hostage. • Rhino horns are prized in some Asian cultures as an ingredient for traditional medicines believed to be effective in treating ailments ranging from fever to cancer.