BILLINGS – An environmental group has sued federal officials over the potential transfer of the National Bison Range to American Indian tribes in Montana.

The lawsuit was filed Monday by attorneys for Public Employees for Environmental Responsibility in U.S. District Court in Washington, D.C.

It says federal officials failed to conduct an environmental review before deciding to support the transfer of the bison range near Moiese to the Confederated Salish and Kootenai Tribes.

Former bison range employees also were named as plaintiffs in the case against the U.S. Fish and Wildlife Service.

Wildlife service spokeswoman Anna Munoz said the agency supports legislation to transfer the range to the tribes. She said under that proposal the range would continue to be managed to maintain its herd of 300 to 400 bison.