An agricultural leader protesting illegal deforestation was shot to death in northern Brazil, the eighth environmentalist farmer to be killed since May in the Amazon, activists said Tuesday.

Joao Chupel Primo, 55, was killed Saturday "because he condemned illegal deforestation in Itaituba," a southwestern region of Para state, Pastoral Land Commission spokesman Gilson Rego told AFP.

"He was receiving death threats and had already been physically abused."

Para prosecutors asked federal police to grant protection to two other farmers who have protested illegal deforestation before public authorities.

For the CPT, a rights group tied to the Catholic Church, Chuper Primo's murder was closely tied to his protests.

"In early October, a police operation sought to halt illegal deforestation near Itaituba after Chupel Primo's protests. This led to increased tension in the region but Chupel Primo continued his denunciation of illegal deforestation," Rego said.

Seven other farmers have been killed since May in Para and Rondonia states amid growing frictions over land conflicts in the Amazon region.

In May, unknown gunmen shot and killed Jose Claudio Ribeiro da Silva, 52, and his wife Maria do Espirito Santo da Silva, 51, after the pair had received death threats since 2008 over their work to preserve the rainforests and prevent illegal deforestation.

They had been working for CNS, an Amazon-focused non-governmental group set up by legendary environmental activist Chico Mendes who himself was killed in 1988.