WASHINGTON (Reuters) - Former congresswoman Gabby Giffords, grievously wounded in a 2011 mass shooting, made an emotional plea on Wednesday for Congress to take action to curb gun violence in the aftermath of last month's Connecticut school massacre, urging lawmakers to "be bold, be courageous."

Wearing a red jacket and speaking haltingly, Giffords opened testimony at the first congressional hearing on gun violence since the December 14 incident in which a gunman shot dead 20 children and six adults at an elementary school in Newtown, Connecticut.

Responding to outrage across the country following that massacre, President Barack Obama and other Democrats have asked Congress to pass the largest package of gun restrictions in decades.

"This is an important conversation for our children, for our communities, for Democrats and Republicans," Giffords, who survived a head wound in an assassination attempt last year in Tucson, Arizona, told the Senate Judiciary Committee. Six people were killed and 13 wounded in the incident.

"Speaking is difficult. But I need to say something important," she told the senators. "Violence is a big problem. Too many children are dying - too many children. We must do something. It will be hard. But the time is now."

Accompanied by her husband, former astronaut Mark Kelly, she concluded: "You must act. Be bold, be courageous. Americans are counting on you. Thank you." She did not take questions from the committee.

Obama's proposals to curb gun violence include reinstating the U.S. ban on military-style assault weapons, limiting the capacity of ammunition magazines, and more extensive background checks of prospective gun buyers, largely to verify whether they have a history of crime or mental illness.

Wayne LaPierre, executive vice president and CEO of the powerful pro-gun lobbying group the National Rifle Association, said the proposals would not reduce gun violence and called for more active prosecution of current laws and improved protection for schools, including armed guards.

"Law-abiding gun owners will not accept blame for the acts of violent or deranged criminals," LaPierre said. "Nor do we believe the government should dictate what we can lawfully own and use to protect our families."

The proposals face a difficult challenge getting through the Democratic-led Senate and Republican-led House of Representatives, where many Republicans and some pro-gun Democrats have long opposed stronger restrictions.

NRA OPPOSES CHANGES

The background check provision is regarded as the gun-control measure most likely to receive bipartisan support. Some Republicans have joined Democrats in emphasizing better background checks of gun buyers, rather than Obama's plan to ban the sale of rapid-firing assault weapons like the one used in the Connecticut shootings.

In a feisty exchange with Judiciary Committee Chairman Patrick Leahy, a Vermont Democrat, LaPierre said his group did not support the proposals to close loopholes on background checks for all gun buyers.

"I do not believe, the way the law is working now unfortunately, that it does any good to extend the law," LaPierre said.

Federally licensed firearms dealers are required to run background checks for criminal records on gun buyers. But the government estimates that 40 percent of purchasers avoid screening by getting their guns from private sellers, including those at gun shows.

The White House's plan would require screening for all prospective buyers.

Kelly, who also testified, and Giffords recently founded Americans for Responsible Solutions, a group intended to combat gun violence.

"Gabby and I are pro-gun ownership. We are also anti-gun violence. And we believe that in this debate, Congress should look not towards special interests and ideology - which push us apart - but towards compromise, which brings us together," Kelly told the senators.

Leahy made clear whatever measures would be considered to rein in gun violence, there would be no move to erode the fundamental right of Americans to own a gun, which is protected under the Second Amendment of the U.S. Constitution.

"Americans have the right to have guns in their home to protect their family," he said.

Republican Senator Jeff Sessions of Alabama, a former federal prosecutor, agreed with the NRA that the government needs to better enforce existing gun laws.

"You have to prosecute," Sessions said.