The Swiss proposal, among other things, requires regular training on the use of firearms, special waivers to own some semi-automatic weapons and a serial number tracking system for key parts of some guns.
Gun owners would have to register any weapons not already registered within three years, and keep a registry of their gun collections.
Supporters of the measure, who included the Swiss Parliament and executive branch, said similar measures adopted by the EU after deadly extremist attacks are needed to ensure strong police cooperation and economic ties with Switzerland's partners in Europe's Schengen visa-free travel zone. They insisted it will not block law-abiding citizens from obtaining legal guns, but would simply do more to track them.
Switzerland is not an EU member, but it is in the Schengen zone.
Opponents insisted the proposal would violate Switzerland's constitution and do little to fight extremism or crime.
They said the weapons used in recent attacks in Europe weren't obtained legally. They argued the proposal cracks down mainly on lawful gun owners in Switzerland and rams through what they see as the latest diktat from Brussels.
Jean-Luc Addor, a populist Swiss People's Party lawmaker from the southwestern Valais region, said adopting the EU directive would be "unjust, freedom-killing, useless, dangerous, and above all, anti-Swiss".
"With no effect on the fight against terrorism, it will only hit honest, law-abiding citizens who possess legal weapons," he wrote on his website. "It's the epitome of injustice."
Carmelo Lagana, project manager for foreign trade at economiesuisse, the country's top business federation, insisted Switzerland would suffer if Swiss police couldn't continue to have access to Schengen-zone databases. He also said the country had an important say in negotiations with the European Union.
Switzerland hasn't faced major extremist attacks like those that have hit France, Belgium, Britain and Germany in recent years, leaving scores dead.
Ahead of the vote, most of Switzerland's major political parties — except for the populist Swiss People's Party — favoured the measure, with support strongest among Socialists and Greens.
The rift on the issue has fallen along a rural-urban divide, with city dwellers more inclined to back the EU directive.
- AP