The Supreme Court on Thursday blocked a $10 billion lawsuit Mexico filed against top firearm manufacturers in the U.S. alleging the companies' business practices have fueled tremendous cartel violence and bloodshed.

The unanimous ruling tossed out the case under U.S. laws that largely shield gunmakers from liability when their firearms are used in crime.

Big-name manufacturers like Smith & Wesson had appealed to the justices after a lower court let the suit go forward under an exception for situations in which the companies themselves are accused of violating the law.

Mexico had asked the justices to let the case play out, saying it was still in its early stages.

The case began in 2021, when the Mexican government filed a blockbuster suit against some of the biggest gun companies, including Smith & Wesson, Beretta, Colt and Glock.

RELATED STORY | Supreme Court upholds Biden rule requiring serial numbers, background checks for 'ghost guns'

Mexico has strict gun laws and has just one store where people can legally buy firearms. But thousands of guns are smuggled in by the country's powerful drug cartels every year.

The Mexican government says at least 70% of those weapons come from the United States. The lawsuit claims that companies knew weapons were being sold to traffickers who smuggled them into Mexico and decided to cash in on that market.

The companies reject Mexico's allegations, arguing the country's lawsuit comes nowhere close to showing they're responsible for a relatively few people using their products to commit violence.

A federal judge tossed out the lawsuit under a 2005 law that protects gun companies from most civil lawsuits, but an appeals court revived it. The 1st U.S. Circuit Court of Appeals in Boston found it fell under an exception to the shield law for situations in which firearm companies are accused of knowingly breaking laws in their business practices.

That exception has come up in other cases, including in lawsuits stemming from mass shootings.

RELATED STORY | US warns of kidnappings linked to dating apps in Mexico

Families of victims of the 2012 mass shooting at Sandy Hook Elementary School in Newtown, Connecticut, for example, argued it applied to their lawsuit because the gunmaker had violated state law in the marketing of the AR-15 rifle used in the shooting, in which 20 first graders and six educators were killed.

The families eventually secured a landmark $73 million settlement with Remington, the maker of the rifle.