The Maryland House of Delegates passed what would be among the most restrictive U.S. gun-control measures Wednesday, voting to ratchet up the state's already tough rules by requiring fingerprinting of gun buyers, new limits on firearm purchases by the mentally ill, and bans on assault weapons and magazines that hold more than 10 bullets.

The 78-61 vote handed Gov. Martin O'Malley a key policy victory as Maryland joins the ranks of Democratic-leaning states passing broad gun-control restrictions in response to the December school shootings in Connecticut — a state where lawmakers Wednesday also passed tough new gun legislation.

The bill now returns to the state Senate, which passed a substantially similar version of the legislation last month. Key senators and staffers said they expect the chamber to sign off on changes made by the House and send the measure to Gov. O'Malley, a Democrat who proposed the legislation.