More than 100 members of the Caravan for Peace arrived in Washington this week to dramatise their call for an end to the war on drugs. They are led by well-known Mexican poet Javier Sicilia, whose son was tortured and killed by drug gangsters.

After visiting 26 cities in the US and Mexico and travelling 10,000 km (6,200 miles), these relatives of drug war victims are asking US officials to take action to end the conflict. They say the war has claimed as many as 60,000 lives over the past six years and done nothing to curb the violence of the cartels.

A father's grief, a nation's response

Sicilia, who was one of TIME magazine's Persons of the Year in 2011, started the movement after his 24-year-old son and several of his son's friends were gruesomely murdered for offending a narco-thug. Sicilia, also a leader of the Movement for Peace with Justice and Dignity, says he began campaigning as a way to deal with his grief. The powerful response from thousands of family members of other victims became an outpouring of support for calling a truce in the drug war.

Sicilia advocates legalising drugs to remove them from the black market, treating drug addiction as a public health problem rather than a crime, and curbing the flow of guns from the US into Mexico. A US Senate report last year found 70% of the weapons seized from Mexican narcotistas came from the US.

Sicilia points out that the militarized approach of the Mexican government towards the drug gangs has succeeded in capturing, killing or driving underground many key drug cartel heads. But the result is that those still lucrative enterprises are now adrift. They are run by mobsters who wage war among themselves and have no compunctions about killing outsiders, journalists, police or anyone else who gets in their way.

Fed up!

The movement – informally known as Hasta la Madre!, or Fed up! – has joined with victims of drug violence in US cities, especially in the Latino and African American communities, to push for more humane and sensible drug policies.

"Forty-plus years after US President Nixon declared the drug war," Sicilia says, "it is time to concede it hasn't worked any more than alcohol prohibition worked back in the 1920s."

Read more: This powerful photo essay by the Atlantic features intimate and stark images of the toll the drug war is taking on all sides of Mexican society. Many of these pictures are quite graphic, but convey the reality of the war on drugs.