Like many of his counterparts, Massachusetts Governor Charlie Baker included gun stores on the list of "non-essential" businesses ordered to close their doors during the pandemic.

But his decision was quickly contested in court by store owners and gun rights groups, who argued that the closures violated the Second Amendment of the US Constitution, which guarantees "the right of the people to keep and bear arms."

The decision from US District Judge Douglas Woodlock in Massachusetts on Thursday was the first to order gun shops' reopening.

A judge in Los Angeles rejected a similar suit filed against cities in California. Cases in other states where gun stores are closed are pending.

Woodlock ruled that Massachusetts gun shops can reopen from Saturday. But people in the stores would be required to follow precautionary measures, such as observing social distancing and wearing masks, according to a copy of the court documents seen by AFP.

With more than 75,000 deaths, the US is by far the country worst-hit by the coronavirus.

At the start of the pandemic, Americans -- with a third of adults already owning at least one firearm -- rushed to buy guns and stock up on ammunition.

While gun stores are considered "essential" businesses in Texas, Ohio and Michigan, states such as New Jersey and New York -- the country's epicenter of the crisis -- took the opposite position.