Speaking to a Democratic National Committee meeting, the frontrunner for the party's presidential nomination blasted Republican candidates for opposing measures she hopes would reduce firearm deaths in the country.

"No one is standing up and saying what we all know to be true: We need to put an end to the gun violence that plagues our communities," she said, to loud applause.

"After the terrible events of Wednesday, with two journalists killed on live television, plus a police officer killed in Louisiana, and many more lost every day in carnage that largely goes unnoticed now across our country, I don't know how anyone could not come to the conclusion that something is deeply wrong," she added.

The United States has more firearms in private hands per capita than any nation on earth, and its firearms deaths per capita are the worst in the developed world.

After a deranged man used a semi-automatic rifle to kill 20 children and six adults at an elementary school in late 2012, congressional Democrats introduced legislation that would have expanded background checks for gun buyers.

But the measure, as well as an assault weapons ban, was rejected by Republicans and some Democrats from conservative-leaning districts.

"I believe we can have commonsense gun reforms that keep weapons out of the hands that should not have them -- domestic abusers, the violently unstable -- while respecting the rights of responsible gun owners," Clinton said.

"I know that the politics are hard. I know that some would rather throw up their hands or give up the fight," she added.

"But not me. I am not going to sit by while more good people die across America."

Several Republican presidential candidates have denounced the Virginia shootings but cautioned against restricting Americans' constitutional right to bear arms.

"This isn't a gun problem, this is a mental problem," Republican frontrunner Donald Trump, the billionaire real estate tycoon, told CNN on Thursday.