The US Supreme Court has restricted the rights of state and city governments to enforce controls on gun ownership.
The country’s highest court ruled by 5-4 that a ban on handgun ownership in Chicago was unconstitutional.
Justices said the US Constitution protected the right to keep and bear arms for the purpose of self-defence.
The ruling could potentially change laws on gun ownership in many of the US states.
Debate over the exact meaning of the constitutional right to keep and bear arms has raged for years in the US.
Two years ago, the court ruled a ban on handguns in Washington DC was unconstitutional – declaring that the Second Amendment protects an individual’s right to possess guns, at least for purposes of self-defense in the home.
But Washington is a federal city, with a unique legal standing. Gun rights proponents almost immediately filed a federal lawsuit challenging gun control laws in Chicago, Illinois, and its suburb of Oak Park, where handguns have been banned for nearly 30 years.
In Monday’s ruling on that challenge the justices said the Second Amendment right “applies equally to the federal government and the states”.
Correspondents say the ruling will be seen as a blow to efforts to reduce the role of firearms in American life.
Strictest controls
The justices seen as the more liberal – Stevens, Breyer, Ginsburg and Sotomayor, voted against the latest ruling.
The case was brought by four Chicago residents as well as local firearms rights activists and the National Rifle Association.
Both Chicago and the Illinois suburb of Oak Park have bans on handguns, making them the strictest areas in the US for gun control laws.
The latest Supreme Court decsion does not explicitly strike down the Chicago area laws, but it orders a federal appeals court to reconsider its ruling – leaving little doubt that the laws will eventually be overturned.