Police in Rio were following a "shoot first, ask questions later" policy as extra-judicial murders soared in the city, according to Amnesty International's report released Monday called "You killed my son: Killings by military police in Rio de Janeiro."

The human rights watchdog said its report covered statistics and analyses ahead of the Rio Olympic Games, which are due to take place next year.

There is "strong evidence" that 1,519 homicides, nearly 16 percent of the total killings, "took place at the hands of on-duty police officers," AI said in its report.

"Rio de Janeiro is a tale of two cities. On the one hand, the glitz and glamour designed to impress the world and on the other, a city marked by repressive police interventions that are decimating a significant part of a generation of young, black and poor men," said Atila Roque, AI's Brazil director.

In an attempt to curb violence, the government has deployed around 85,000 police officers and soldiers in Rio de Janeiro as the city prepares for the Olympic Games, especially around the sports venues, hotels and beaches.

Rampant violence and the high murder rate continue to make headlines in Brazil. The South American nation has one of the highest rates of violence among not-at-war countries. According to the UN, more than 50,000 people were killed in the country in 2012. The number, however, dropped last year, which was partly a result of the increased security in Brazil's major cities and a police crackdown on drug cartels.

"Brazil's failed 'war on drugs' strategy to tackle the country's very real drug and violence public security crisis is backfiring miserably and leaving behind a trail of suffering and devastation," said Roque. "Too many lives are lost to the toxic cocktail of a corrupt violent and ill-resourced police force, communities so poor and marginalized they are hardly visible and a criminal justice system that constantly fails to deliver justice and reparations for human rights violations."