WASHINGTON (Reuters) - U.S. police make over 1.25 million arrests a year for drug possession, more than twice the number for violent crimes, and about half of the arrests are for marijuana, two human rights groups said on Wednesday in a call for sweeping drug decriminalization.

An illegal indoor cannabis production operation using grow lights is seen at a house in McKinleyville, California U.S. August 28, 2016. REUTERS/Rory Carroll

The 196-page report by the American Civil Liberties Union and Human Rights Watch said the “war on drugs” was a failure, with rates of drug use unchanged since President Richard Nixon launched the campaign more than 40 years ago.

States and the federal government should decriminalize the use and possession of drugs for personal use and focus instead on prevention and reducing harm, the report said.

“These wide-scale arrests have destroyed countless lives while doing nothing to help people who struggle with dependence,” Tess Borden, the report’s author, said in a statement.

The report said nearly half of all drug possession arrests in 2015, or more than 574,000, were for marijuana, based on Federal Bureau of Investigation figures.

In the same year, there were 506,000 arrests for violent crimes such as murder, rape and aggravated assault, FBI data showed. Four times as many people are arrested for possessing drugs than distributing them, the report said.

Even though whites are more likely than black people to use illicit drugs in the course of their lives, adult African-Americans are more than 2.5 times more likely to be arrested for drug possession, the report said.

The report came as five U.S. states - Massachusetts, Maine, California, Arizona and Nevada - prepared to vote on Nov. 8 on legalizing recreational use of marijuana. Four states and the District of Columbia allow possession of small amounts for personal use.

A growing number of Americans back legalizing marijuana, with 57 percent saying it should be made legal in a Pew Research Center poll released on Wednesday.

The report by the ACLU and Human Rights Watch on the impact of drug possession arrests was based on more than 365 interviews between October 2015 and March 2016 that included drug offenders, family members and prosecutors. It also used data provided in response to public information requests.