ZURICH/GENEVA (Reuters) - Swiss voters agreed by a nearly two-to-one margin on Sunday to adopt tighter gun controls in line with changes to European Union rules, heading off a clash with Brussels.

The measure passed in the binding referendum under the Swiss system of direct democracy by a 64-36% margin, provisional final results showed.

The restrictions, which apply to non-EU member Switzerland because it is part of Europe’s Schengen open-border system, had raised hackles among shooting enthusiasts ahead of the vote.

Failure to adopt the rules could have forced Switzerland to leave the passport-free Schengen zone and the Dublin joint system for handling asylum requests.

After militants killed scores of people in Paris in 2015, the EU in 2017 toughened laws against purchasing semi-automatic rifles such as the ones used in those attacks and made it easier to track weapons in national databases.

The initial EU proposal provoked an outcry because it meant a ban on the Swiss tradition of ex-soldiers keeping their assault rifles.

Swiss officials negotiated concessions for veterans and gun enthusiasts who take part in the country’s numerous shooting clubs, but any restrictions imported from the EU go too far for right-wing activists concerned about Swiss sovereignty.

“To me, the new obligations linked to the possession of guns are not that restrictive, while the risk of not being able to benefit from Schengen’s advantages are very real,” said one bank employee who gave his name only as Philippe.

“It has nothing to do with blackmail, it is just that Switzerland has to align itself with a system to which it participates.”

Slideshow ( 7 images )

Gun rights proponents complained the rules could disarm law-abiding citizens and encroach on Switzerland’s heritage and national identity, which includes a well-armed citizenry.