The World Wide Fund for Nature is urging tourists to boycott Thailand until that country ends an illegal trade in wildlife which threatens some of the world's rarest species.

"Thailand is probably the worst country in the world for the illegal trade in endangered wildlife," Simon Lyster, a senior conservation officer for the fund, told a London news conference Thursday."If allowed to continue, this illegal trade could drive some species to extinction," Lyster said.

Rhinos, Asian elephants, tigers and hyacinth macaws are among the species threatened because Thailand flouts the Convention on International Trade in Endangered Species, Lyster said. Thailand is a member of the convention, which took effect in 1975.