Two members of Brazil's landless activist group MST were killed yesterday in a rural area in the northeast state of Paraba, according to MST and local police.
The two men were killed on a farm where activists of the left-wing MST group put up a camp last year.
Brazil's far right President-elect Jair Bolsonaro has said activism by MST should be considered as terrorism and there are fears his position could stimulate more violence in Brazilian rural areas.
MST said in a statement that heavily-armed men entered the camp and shot the two men dead.
Police at the Alhandra municipality confirmed the deaths, but said it still lacked details of what it called homicides.
It said two police deputies from the state's capital Joao Pessoa were sent by the government to help investigate the shooting and were at the farm today talking to witnesses.
No suspects had been identified or arrested, the police said, and the bodies of the activists were still at the farm.
They would be transferred to the city later for the autopsies.
MST said the men killed were Jose Bernardo da Silva and Rodrigo Celestino.
MST activists fight for equitable land distribution in Brazil, many occupying areas they say are not producing anything and then seeking its expropriation by the government.
The group demanded a quick investigation of the crime and the arrest of the killers.
Killings related to land disputes in Brazil reached 70 last year, according to Comissao Pastoral da Terra (CPT), a group linked to the Catholic church.
It said in a report in April that it was the highest amount of such deaths since 2003, when 73 people were killed in land conflicts.