Washington DC - President Donald Trump on Wednesday signed into law a landmark bill imposing draconian sentences for possession and trafficking of fentanyl-related substances.

Families affected by what has been described as a fentanyl epidemic in the US joined Trump at the White House as he put the finishing touch on legislation passed by Congress in June.

The HALT Fentanyl Act permanently classifies copycat variations of fentanyl – which are often cheaper to make – as Schedule 1 drugs, which mandates harsh sentences for possession, manufacturing, or trafficking.

Trump hailed it as "a righteous blow to the drug dealers, narcotic traffickers, and criminal cartels."

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He added: "We take a historic step toward justice for every family touched by the fentanyl scourge."

Anne Fundner, who lost her son to a fentanyl overdose and was present at the event, called the act "a lifeline for families across America for keeping our families safe."

According to the Justice Department, some 75,000 Americans die each year because of fentanyl, making it the number one cause of death for people between the ages of 18 and 34 in the country.

But civil rights organizations have warned that the mandatory minimum sentences mandated by the HALT Fentanyl Act will only add to the systemic problem of mass, racialized incarceration – virtually repeating the mistakes of the disastrous "War on Drugs."