Two environment groups on Monday sued the Trump administration over its efforts to let the heads of African elephants and lions be imported to the United States.

The suit, filed in federal court in Washington D.C. by the Center for Biological Diversity and Natural Resources Defense Council, charges that President Trump’s decision to allow big-game hunters to import the remains of elephants and lions hunted legally in Zimbabwe and Zambia violates the Endangered Species Act.

However, Trump said last week that he was temporarily reversing his decision to lift the Obama-era ban on importing big game hunting trophies into the US just days after the US Fish and Wildlife Service said it will begin issuing permits for elephant trophies from Zimbabwe and Zambia.

On Sunday night, Trump said in a tweet: “Big-game trophy decision will be announced next week but will be very hard pressed to change my mind that this horror show in any way helps conservation of Elephants or any other animal.”

Elephants and lions are listed under the Endangered Species Act.

“The Trump administration must clearly and permanently halt imports of lion and elephant trophies to protect these amazing animals from extinction,” Tanya Sanerib, a senior attorney with the Center for Biological Diversity, said in a statement Monday.

“Trump’s abrupt backpedaling after public outcry, while appreciated, shows how arbitrary this deplorable decision was. These incredibly imperiled creatures need a lot more than vague promises,” the statement continued.

The lawsuit claims that the Trump administration acted arbitrarily in moving to reverse the Obama-era 2014 ban.

“Putting trophy imports ‘on hold’ isn’t enough,” Elly Pepper, the deputy director of Wildlife Trade for the Natural Resources Defense Council, said in a statement. “Elephants are in crisis now. If we don’t force the Administration to completely revoke its decision, President Trump could quietly start allowing these imports as soon as he stops facing criticism on Twitter.”