A few years ago, under the Obama administration, the U.S. Fish & Wildlife Service (FWS) banned the import into the U.S. of elephant trophies from Zimbabwe, regardless of whether the beasts had been legally hunted there. Now it seems the ban has been lifted, along with that on imports from Zambia, with no real explanation yet as to why.

Conservationists are deeply concerned about the decision. “[As] the current political, social and economic climate in Zimbabwe is fragile without any accountable government, it is worrisome that the [U.S.] would allow imports from a country whose political future is uncertain,” Michael Chase, the founder and director of Botswana-based Elephants Without Borders, told Fortune. Even without the factor of political instability, Chase described Zimbabwe’s recent elephant conservation research and management as “failing.”

Under the international Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), and under the U.S. Endangered Species Act, elephants are classified as endangered species. However, if a country is successfully working to conserve and increase their elephant populations, it’s supposed to be acceptable for hunters to bring home the ivory from their kills in that country, as the fees from the hunting permits can aid those conservation efforts.

In 2014, the FWS said that additional elephant hunting in Zimbabwe, “even if legal, is not sustainable and is not currently supporting conservation efforts that contribute towards the recovery of the species.” So American hunters couldn’t bring home their elephant trophies.

Now, as first revealed by the pro-hunting lobby group Safari Club International (SCI), the FWS has lifted its bans on bringing elephant remains into the U.S. from Zimbabwe, as well as from neighboring Zambia.

“We appreciate the efforts of the Service and the U.S. Department of the Interior to remove barriers to sustainable use conservation for African wildlife,” SCI president Paul Babaz said. Interior secretary Ryan Zinke set up an “International Wildlife Conservation Council” to advise him, just days ago.

“Legal, well-regulated sport hunting as part of a sound management program can benefit the conservation of certain species by providing incentives to local communities to conserve the species and by putting much-needed revenue back into conservation,” the agency said in a statement.

However, as The Washington Post has pointed out, the FWS didn’t say what had changed in Zimbabwean conservation practices to make the change acceptable. The agency said it would reveal more on Friday.

Zimbabwe has Africa’s second-largest elephant population, after Botswana. However, last year the Great Elephant Census—an initiative backed by Microsoft co-founder Paul Allen—showed that elephant numbers in Zimbabwe continue to decline. Elephants Without Borders assisted in that aerial survey.

“The elephant population in Zambia has suffered a dramatic decrease over the last few decades, from more than 200,000 elephants in 1972 to just a little over 21,000,” said Chase. “Poaching and the illegal ivory trade remain a threat to the country’s and transborder elephant populations. I have no evidence to suggest that the elephant population in Zambia is stable or increasing.”

“This recent decision rewards countries that have a dubious conservation track record, and which will further threaten elephant populations in their last stronghold in southern Africa. Elephant numbers in many parks in Zambia are so depressed that poachers are turning to killing elephants in neighboring countries such as Angola, Botswana and Zimbabwe.”

Even Fox News, usually a reliable supporter of the Trump administration, has expressed concern at the move: