Amnesty International has warned that the persecution of human rights campaigners in parts of the Americas is reaching emergency proportions.
Colombia's President Uribe's policies are singled out for criticism
The organisation says activists continue to be threatened, tortured and sometimes killed for trying to draw attention to rights violations.
Amnesty argues that the US-led "war on terror" has been misused by some governments to persecute campaigners.
The report was published by leading Amnesty members on a visit to Brazil.
Amnesty International has documented more killings of human rights campaigners in the region than anywhere else in the world.
This report contains shocking examples, like the case of an activist in Guatemala who was found dead with his tongue and ears cut off - and the killings of three environmental campaigners in Honduras, allegedly by security guards working for a logging company.
Amnesty says that many governments in the region fail to take such violations seriously, and that all too often, politicians portray human-rights campaigners as subversives in legal with criminals or terrorists.
"Human rights defenders are speaking about certain principles - principles of justice and equality - that need to be applied fairly to everyone," said the organisation's secretary-general, Irene Khan.
"There needs to be an understanding on the part of governments that when human rights defenders criticise these issues, they are actually performing a very important role in democratic society and that they're not enemies of the state."
This report also says that the United States Government and others have misused new security measures to hamper the work of human rights groups, and sometimes to target the activists themselves.
Colombia is singled out as the worst offender.
Amnesty International says the security policies of President Alvaro Uribe have led to a wave of arbitrary arrests.
Since August of last year, 15 human rights campaigners have been killed in Colombia.