WASHINGTON — The Supreme Court turned away an appeal from Maryland gun owners who challenged the state's ban on the assault weapons, which were used in recent mass shootings in a south Texas church and at an outdoor concert in Las Vegas.

The justices left in place a federal appeals court ruling that cast doubt on whether ownership of assault weapons is protected by the Constitution, while upholding the Maryland law that does not permit the sale of a range of semi-automatic weapons and large-capacity magazines.

In the 4th Circuit Court of Appeals ruling earlier this year, Judge Robert King wrote "we have not power to extend Second Amendment protections to weapons of war."

Get Breaking News Delivered to Your Inbox

Maryland Attorney General Brian Frosh, who pushed for the legislation as a state senator in 2013, said he hoped the appeals court's ruling and the high court's decision not to review it would encourage other states to adopt similar protections.

"It ought to be a lesson to all states, and I would hope that they would look at the 4th Circuit's decision and the tragic events around the country and come to the conclusion that this is a common-sense law," said Frosh, a Democrat.

Maryland passed the sweeping gun-control measure after the 2012 Sandy Hook Elementary School massacre that killed 20 children and six educators in Connecticut. It bans 45 kinds of assault weapons and puts a 10-round limit on gun magazines.

"This success is even more significant as we near the five-year anniversary of the horrific tragedy at Sandy Hook Elementary School," said Jen Pauliukonis, president of Marylanders to Prevent Gun Violence. "While Congress may continue to fail to act, state legislatures must take the lead in protecting American citizens from the atrocities of gun violence in our communities."

The high court has not re-entered the debate over guns since rulings in 2008 and 2010 that held that Americans have a constitutional right to have guns for self-defense in their homes and that local governments could not ban handguns.

The justices also declined an appeal asserting a constitutional right to carry firearms openly in public.