NEW YORK - Hundreds of men, women and children including fashion designer Donna Karan marched across the Brooklyn Bridge on Saturday demanding stricter gun laws and offering a litany of violent stories to show why such laws are needed.

Held on the eve of Mother's Day, the third annual march from Brooklyn to Manhattan was organized by the group Moms Demand Action for Gun Sense in America.

"Progress is being made, one day at a time," said Abbey Clements, a teacher from the Sandy Hook Elementary School in Newtown, Conn., where a gunman killed 20 children and six adults in December 2012.

Clements said about 40 percent of all gun sales are completed without a background check. She accused Congress of lacking the courage "to vote on their conscience instead of allowing themselves to be bullied by the gun lobby."

But she noted that some states have tightened background check requirements. Connecticut already has strong gun laws, with relatively fewer gun deaths, she said.

The National Rifle Association, the nation's largest gun rights lobbying group, opposes expanding background checks. The organization says many people sent to prison because of gun crimes get their guns through theft or the black market, and no amount of background checks can stop those criminals.

Legislation that sought to expand background checks to all commercial firearms sales failed to get a hearing in the U.S. House last session. With the GOP expanding its majority and winning control of the U.S. Senate, prospects for the bill may be even more unlikely this session.

Under the current system, cashiers at stores selling guns call in to check with the FBI or other designated agencies to ensure the customer doesn't have a criminal background. Some lawmakers want to expand such checks to sales at gun shows and purchases made through the Internet.

The nation averages more than 80 gun deaths each day, according to the Centers for Disease Control and Prevention.

"We have more gun-related deaths than any other developed country. Gun deaths now outpace traffic fatalities in our country," said U.S. Rep. Carolyn Maloney, D-NY. "It may take years, it may take decades, but the tens of thousands who senselessly lost their lives at the barrel of a gun will not be forgotten."

As they crossed the bridge, participants yelled, "Not one more!"

The march ended with a rally outside City Hall in lower Manhattan.

Christopher Underwood, 8, addressed the crowd three years after losing his 14-year-old brother to gunfire in Brooklyn's Bushwick neighborhood.

"It made me sad, because he was the only one who dropped me off at school, and I miss him," said the boy, whose brother was killed when a bullet ripped through his brain. "I'm still scared."

Edwin Guzman sat behind the stage holding a poster with photos of his daughter. Samantha Guzman was 18 when she left a Bronx party in 2006 with friends on Mother's Day and was shot to death in the street - a week before her high school prom.

"New York has come a long way; the gun laws have gotten stronger," Guzman said.

However, he noted, many of the guns used in New York are smuggled from out of state, including the one that took the life of Officer Brian Moore last Saturday. Police traced the Taurus Model 85 revolver to a pawn shop in Georgia where it was stolen.