Natalie DiBlasio

USA TODAY

WASHINGTON -- Sonja Woods says she came to Capitol Hill on Wednesday because her daughter was fatally shot by a man who flunked multiple background checks to buy a gun due to mental problems. So he bought the weapon at a hardware store that did not require a background check.

Woods joined scores of gun violence survivors and family members of victims who gathered in a crowded congressional conference room to kick off the second annual "Moms Take the Hill" event and Mother's Day "Week of Action."

"I am speaking out to honor the life of my daughter who was murdered by a man who should not have been eligible to purchase a gun," Woods said, choking back tears.

Mothers and activists are spending the week meeting with their representatives and making their case for demand universal background checks on gun buyers. In an effort to rally more support, members of the group have been hosting house parties in their home states, trying to get their neighbors to join in.

"We are taking this fight to the states," says Shannon Watts, founder of Moms Demand Action for Gun Sense in America. "What we want Congress to know is that we are watching them, but we are not waiting for them. We are getting ready for the midterms and we are going to hold them accountable for their failure to act."

During last year's "Moms Take the Hill" event, the group had chapters in a handful of states. Now, the group claims to include rapidly growing chapters in all 50 states.

"What you see gathered here today are moms taking the hill. We know that with the right to protect oneself comes great responsibility," said Lucia McBath, whose son Jordan Davis was shot and killed. "We are in this for the long haul and we are not backing down."

Moms Demand Action and Mayors Against Illegal Guns recently came together to form a new group named Everytown for Gun Safety. Last month, former New York City mayor Michael Bloomberg pledged to spend $50 million this year to support the organization.

Larry Pratt, executive director at Gun Owners of America, is no fan of the effort. "We invite him to waste his money," Pratt told USA TODAY. "That group isn't going to do anything he promises."

"Background checks are a complete and total waste of time and money, Pratt said. "They aren't going to stop bad guys getting guns."

Long-term goals of Everytown are comprehensive background checks for gun buyers, enhanced protections for domestic violence victims and to address child access to guns. The group says it hopes to undercut the National Rifle Association's political power in Washington.

NRA officials did not return a call for comment, but the group has consistently fought curbs on gun sales.

The "NRA's 5 million members and America's 100 million gun owners will not back down — not now, not ever … mark my words: The NRA will not go quietly into the night. We will fight," Executive Vice President Wayne LaPierre said in a prepared statement for the NRA's recent convention in Indianapolis. "History has proven again the truth that President Obama and the anti-freedom activists everywhere deny and try to suppress the truth that firearms in the hands of good people save lives."