Members of Brazil's Cabinet decided at an emergency meeting in Brasilia that if necessary, the activists will receive protection from the national armed forces, The Rio Times reported Tuesday.
Minister Gilberto Carvalho, head of the Presidential General Secretariat, said the government is concerned about the deadly violence directed at the environmentalists.
"Our top priority is to provide protection by coordinated action by the federal and state governments," he said.
The latest of the four Amazon activists to be killed was Adelino Ramos, 57, a farmer and leader of the Corumbiara Peasant Movement in the state of Rondonia. He was gunned down Friday as he was selling roadside vegetables, the Times said.
His slaying followed those of Jose Claudio Ribeiro da Silva, 52, and his wife Maria do Espirito Santo da Silva, 51, in the state of Para, and Eremilton Pereira dos Santos, a farmer found shot to death in the same area.
Police have said they have found no link between the killings, but they occurred as lawmakers debated changes to Brazil's forest code and the Catholic Church's Pastoral Land Commission says there's a list with 125 names of people who have received death threats.
The justice minister has promised immediate police protection will be offered to those deemed to be in the greatest danger, the Times said.
The Brazilian Congress approved revisions that would ease protections for the Amazon and offer partial amnesties for landowners who have illegally destroyed parcels of the rainforest. The changes have yet to be approved by the Senate or President Dilma Rousseff.
Agricultural Development Minister Afonso Florence maintains "there is no direct association" between the legislative debate and the violence against the environmentalists.
"The debate has another dynamic," he told Brazilian reporters.
Leila Salazar-Lopez, program director of the environmental group Amazon Watch, said the solution is for the government to "end the era of impunity for illegal loggers, ranchers and agribusiness."