RENO, Nev. (AP) — Wild horse advocates are calling for a federal investigation into an emergency mustang roundup in southern Nevada where government officials say more than two dozen had to be euthanized due to severe starvation.

Bureau of Land Management officials say they gathered 201 horses 30 miles west of Las Vegas last week because of extreme drought conditions and a lack of forage. Acting BLM State Director John Ruhs says 28 were killed because of their "poor or extremely emaciated body condition."

He says a veterinarian determined they had a "poor prognosis for recovery or improvement." Anne Novak, executive director of Protect Mustangs, said Wednesday the roundup was "supposed to save wild horses, not kill them." She's asking the Interior Department's inspector general to investigate whether the animals were killed as a convenient way to save money.