President Barack Obama and national media are demonizing law-abiding gun owners in the wake of recent violent acts, National Rifle Association leaders and political allies said on Friday at its first convention since the Connecticut school massacre.

"Our freedom is under attack like never before," Chris Cox, executive director of the NRA Institute for Legislative Action, said during a leadership forum. "When a deranged criminal murders innocent children, they blame us."

The NRA is the nation's leading advocate for gun ownership. It works assiduously to defend the Second Amendment to the U.S. Constitution setting out the right to bear arms.

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Organizers expect some 70,000 attendees at the 142nd NRA Annual Meetings & Exhibits in Houston, which began on Friday and continues through Sunday. Since last year's meeting, a national debate about gun laws sprang up after the December shooting at Newtown, Connecticut's Sandy Hook Elementary School, where 20 children and six adults were killed.

The NRA scored a major victory in Congress last month when it beat back a proposal supported by Obama to expand background checks for gun buyers.

At the leadership forum, U.S. Senator Ted Cruz, a Texas Republican, thanked those who fought against the background checks proposal and other efforts to tighten gun control.

"That's your victory," Cruz said. "It's the victory of the American people."

But Cruz cautioned that the fight is not over. Supporters of the proposal, which is a key part of Obama's gun-control effort sparked by the Newtown shooting, have vowed to revive it.

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Freedom Under Attack: NRA Official