JOHANNESBURG (AP) — Some conservationists oppose the planned relocation of 18 elephants from Swaziland to zoos in the United States, but a U.S. official has said the animal transfer can be done humanely and is permissible under international law.

The U.S. Fish and Wildlife Service last month approved the transfer of the elephants to Dallas Zoo, Sedgwick County Zoo in Wichita, Kansas, and Henry Doorly Zoo in Omaha, Nebraska.

The service's associate director, Robert Dreher, told The Associated Press that he recognizes the "humanitarian concerns" of opponents of the elephant export. However, he said it does not threaten conservation of the species, which is being heavily poached, and that zoos educate the public about wildlife.

"We have looked hard at this," Dreher said Saturday in South Africa's Kruger National Park, one stop on an Africa trip with U.S. Secretary of the Interior Sally Jewell. The American delegation also visited Gabon and Kenya to discuss ways to stop wildlife trafficking.

In a statement, the Dallas Zoo said Swaziland would have had to cull the 18 elephants "to prevent further degradation of the land and to make room for critically endangered rhinos" in its wildlife reserves. It also said regional drought was threatening wildlife in the southern African nation.

However, a group of conservationists said wild elephants often suffer health problems in zoos; there is no evidence that options for relocating elephants in other African parks were explored; and that the relocation has no conservation value.

"It's condemning these wild animals — sentient wild animals — to life imprisonment," said Francis Garrard, director of South Africa-based Conservation Action Trust. He described the elephant project as a commercial venture for the zoos.

Last year, Zimbabwe sent 20 elephants to zoos in China despite similar protests from some conservationists.

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