SACRAMENTO — Following passage last year of some of the strongest gun-control laws in the nation in the wake of the school shooting in Newton, Conn., leading California Democrats will open a new front in the fight against gun violence this year with a proposal to conduct background checks on people who purchase ammunition.

State Senate Democrats will push to require a comprehensive background check on anyone seeking to purchase ammunition, and to require a one-year permit for ammunition purchases.

“Anyone can walk into any gun store, a bait and tackle store, and purchase all the ammunition they want to, no questions asked,” Sen. Kevin de Leon (D), the bill’s lead sponsor, said in an interview. “The ammunition is the fuel that feeds the violence. The gun itself, the hand gun or the long gun or the high-powered weapon is the delivery device. The gas, the fuel, is the ammunition, and no one knows who buys it.”

No other state has gone as far as to regulate ammunition purchases, de Leon said, though gun-control advocates in other state legislatures, including New York, have expressed interest in copying the proposal.

In the wake of the Newtown shootings, the Democratic-controlled California legislature passed some of the strictest gun-control measures in the country last year, including measures to limit the sales of high-capacity magazines, limit access to firearms for the mentally ill and prevent businesses from applying for assault weapons permits.

Gov. Jerry Brown (D) vetoed two other measures that would have defined some rifles and shotguns as assault weapons and banned semiautomatic rifles with detachable magazines last year. The National Rifle Association had threatened a lawsuit if Brown had signed the measures.

But state Senate President Darrell Steinberg (D) said the legislature will address gun-control measures again this year. In an interview, Steinberg said he would push to end loopholes to a ban on assault weapons.

“Our work’s not done there,” Steinberg said. “We want to distinguish in this state guns that are legally owned for sport, for recreation and for self-defense and safety, versus guns and rifles that allow hundreds of bullets to be fired within seconds that can indiscriminately injure or kill people that have no use in the sport, recreation or self-defense categories.”

Brown asked de Leon in the fall to work on the ammunition legislation. Several cities require background checks on ammunition purchases already, including Sacramento; in 2012, the Sacramento Police Department reported that it had tracked 349 people prohibited from owning firearms who nonetheless purchased ammunition. Two hundred seventy-five of those purchasers were convicted felons.