LOS ANGELES - California lawmakers, seizing on new calls for gun controls following the massacre of 26 people at a Connecticut elementary school, rolled out proposals on Tuesday to close loopholes in the state's assault weapons ban and restrict ammunition sales.

The moves quickly put California at the forefront of what was expected to be a new wave of proposed firearm restrictions at the state and federal levels in the wake of the Connecticut school shooting rampage at Sandy Hook Elementary School in Newtown.

State Senator Leland Yee introduced a bill that would prohibit gun owners from fitting semi-automatic weapons with devices, known as "bullet buttons" or "mag magnets," that allow them to be easily reloaded with multiple rounds of ammunition.

The San Francisco Democrat's measure would also prohibit add-on kits that allow high-capacity magazines. He said he was drafting legislation that would require yearly background checks for gun ownership and toughen safety requirements.

His action came as state Senator Kevin De Leon, a Democrat from Los Angeles, said he would introduce a bill this week requiring ammunition buyers in the nation's most populous state to obtain a permit issued by the US Department of Justice.

"For too long, too much ground has been ceded in the debate about reasonable gun and ammunition control," De Leon said in a statement. "In honor of the Sandy Hook Elementary School victims and thousands who have preceded them, we must not capitulate any longer."  

A gunman carrying a semi-automatic rifle and two handguns opened fire on Friday at the Connecticut school, killing 20 young students and six adults in a crime that stunned Americans and renewed calls for stricter gun controls.

De Leon said the one-year, $50 permit, which would require a background check by the Justice Department, aimed to combat the easy accessibility of ammunition.

California gun laws are already among the toughest in the nation, topping a list compiled by the Law Center to Prevent Gun Violence. The state has banned most assault weapons, requires sales be made by a licensed dealer, including at gun shows, and imposes a 10-day waiting period, among other regulations.

Related:

Newtown of Connecticut on healing journey, mystery remains

US authorities release names of school shooting victims

Major school shootings in US since 1999

World shocked by school shooting in US