SÃO PAULO, Brazil  In an unprecedented move against rogue cattle ranchers in the Amazon, the Brazilian government has seized livestock grazing there illegally, the new environment minister announced Tuesday.

Officials carted off 3,100 head of cattle that they said were being raised on an ecological reserve in the state of Para, in an operation intended to serve as a warning to other ranchers grazing an estimated 60,000 head on illegally deforested land in Amazonia, the environment minister, Carlos Minc, said.

“No more being soft,” Mr. Minc told reporters in the capital, Brasilia. “Those that don’t respect environmental legislation, your cattle are going to become barbecue for Fome Zero,” he said, referring to the government’s food program for the poor.

Mr. Minc said the cattle would be auctioned in two weeks and the proceeds go to Fome Zero, as well as to health programs for indigenous peoples and to finance cattle removal operations.