“Put big game trophy decision on hold until such time as I review all conservation facts,” Trump wrote on Twitter. “Under study for years. Will update soon with Secretary Zinke. Thank you!”

Trump’s sudden tweet halted a decision by his own administration, announced by the U.S. Fish and Wildlife Service on Thursday, to end a 2014 government ban on big-game trophy hunting in Zimbabwe and Zambia, saying it would help the conservation of the species. Under U.S. law the remains of African elephants, which are listed as threatened under the Endangered Species Act, can only be imported if federal officials have determined that hunting them benefits the species more broadly.

But the Fish and Wildlife decision almost immediately was met with a fierce backlash and outcry from animal rights activists and environmentalists — as well as prominent conservatives, and a key House committee chairman.