The Secret Service said it would forbid attendees to carry firearms at the Republican National Convention in Cleveland in July, neutralizing an effort by gun rights advocates that had put pressure on the candidates to take a side on the issue.
"Only authorized law enforcement personnel working in conjunction with the Secret Service for a particular event may carry a firearm inside of the protected site," Kevin Dye, a spokesman for the agency, said in a statement Tuesday.
The debate over whether to permit guns at the Quicken Loans Arena in the second-largest city in Ohio flared in the past week after an online petition appeared on Change.org, taking issue with the arena's anti-weapons policy in a state that allows "open carry" of firearms.
"This is a direct affront to the Second Amendment and puts all attendees at risk," said the petition, which had gathered more than 50,000 signatures by Tuesday morning.
(The origins of the petition remain murky, but a CBS News report linked it to a liberal activist who said it had been intended as satire.)
As momentum over the issue grew, the Republican candidates faced increasing pressure to take a position.
Appearing on ABC's "This Week" Sunday, Donald Trump, the GOP front-runner, said that he had yet to review the petition, but added that delegates risked becoming "sitting ducks, utterly helpless against evildoers and criminals."
He said he was a "very, very strong person for the Second Amendment."
The other Republican contenders, Sen. Ted Cruz of Texas and Gov. John Kasich of Ohio, have not commented on the petition, but Cruz has been a vocal opponent of gun-free zones. Messages left with their campaigns Tuesday were not immediately answered.
The fight against gun-free zones has been propelled by Republicans in recent years partly as a response to the drumbeat of mass shootings in the United States. Gun rights advocates have pushed a "good guy with a gun" argument: that licensed gun owners could save lives during such shootings.
Trump, who has a wide lead in the delegate count and is under Secret Service protection, said in January that he would eliminate gun-free zones on "my first day" in the White House.
Among the latest battlegrounds is Texas, where a law was approved last year to allow licensed gun owners to carry them in buildings at state universities, setting off protests by some faculty members and student groups.
The Secret Service said Tuesday that it had the authority to ban guns from sites visited by presidential candidates under its protection.
A perimeter would be set up outside the arena during the convention — July 18-21 — which "individuals determined to be carrying firearms will not be allowed past," Dye said.