On Thursday, Connecticut Gov. Dan Malloy (D) signed into law what is being seen as the most comprehensive gun control legislation in the nation.

In doing so, Connecticut became the third state since the Newtown, Conn., shooting last December to pass strict new gun laws, joining New York and Colorado. 

Connecticut's new law bans the sale of many assault weapons, limits ammunition magazine capacity to 10 rounds, and requires universal background checks for all gun purchases, including those sold privately at gun shows. It also creates the nation's first statewide registry of people convicted of crimes involving weapons.

"This is a profoundly emotional day, I think, for everyone in this room," Malloy said at the signing ceremony. "We have come together in a way that relatively few places in our nation have demonstrated an ability to do."

Connecticut's action underscores the fact that though proposed gun laws have stalled in Congress, efforts at the state level have not.

According to the Law Center to Prevent Gun Violence, which tracks legislative efforts on gun control, over 600 bills aimed at curbing gun violence have been introduced this year alone, a 63 percent increase over the same period in 2012. At least 17 states have introduced bills to limit magazine capacity, while 16 have introduced bills that would require universal background checks, according to the organization.

In addition to the three states that have strengthened their gun laws since the Sandy Hook shooting that left 26 dead, Maryland is expected to do the same shortly. The Maryland House of Delegates passed a bill Thursday that would ban assault-type weapons and limit magazines to 10 rounds. It heads back to the state Senate for final approval, and Gov. Martin O'Malley (D) has already promised to sign it when it reaches his desk.

Meanwhile, on the federal level, gun legislation has gone almost nowhere. Democrats dumped a proposed renewal of the assault weapons ban for lack of support last month, while vowing to push ahead on other measures, like universal background checks. However, even stripped-down gun control proposals are now in doubt. Several Republican senators have said they'll filibuster any bill requiring background checks, a crucial piece of Democrats' efforts to overhaul federal gun laws.

Seeking to rally support for federal action, President Obama is on a mini-tour this week and next touting the tighter gun laws in Colorado and Connecticut. In Denver, he hailed Colorado's new law as "a model for what's possible," and called on Congress to follow suit. 

But while a handful of states have moved to tighten their gun laws, even more states have done the opposite, loosening the restrictions for obtaining a firearm, and rolling back the limits on where people can carry guns. Arkansas, for example, removed a ban on carrying guns in churches and on college campuses.

Still, advocates for more stringent regulations say they hope their efforts will lead other states — and ultimately Washington — to act. 

"Democrats and Republicans were able to come to an agreement on a strong, comprehensive bill," Connecticut Senate President Donald E. Williams Jr. said. "That is a message that should resound in 49 other states, and in Washington, D.C., and the message is we can get it done here and they should get it done in their respective states and nationally in Congress."