By Jeff Mason

FAIRFAX, Va. (Reuters) - President Barack Obama fielded tough questions from gun owners at a televised town hall on Thursday, defending his move to tighten gun rules as he sought to elevate the issue of gun control before the November 2016 election to replace him.

A series of mass shootings has punctuated Obama's time in office, and after he failed to convince Congress to toughen up gun laws, the president said he wanted to have a national debate about guns in his final year in office.

Obama, who said he had never owned a gun, has blamed Congress for being beholden to the National Rifle Association, a powerful lobby group that fights any action that might infringe on Americans' constitutional right to bear arms.

Guns are a potent issue in U.S. politics. The NRA is feared and respected in Washington for its ability to mobilize gun owners. Congress has not approved major gun-control legislation since the 1990s.

The NRA sat out the town hall, aired live on CNN from a university just miles (km) from the group's Virginia headquarters, calling it a "public relations spectacle."

But several gun owners peppered Obama with arguments against his gun rule proposals.

Taya Kyle, widow of U.S. Navy SEAL Chris Kyle who was killed at a gun range and portrayed in the film "American Sniper," said laws would not stop people with criminal intent.

"The problem is that they want to murder," Kyle said.

Kimberly Corban, a survivor of a sexual assault who said she carried a gun to protect herself and her two young children, told Obama that she felt his changes infringed on her rights.

"I have been unspeakably victimized once already, and I refuse to let that happen again to myself or my kids," Corban said.

Obama told Corban his proposals would not make it harder for law-abiding people like her to buy a gun, but could stop some criminals. "You certainly would like to make it a little harder for that assailant to have also had a gun," he said.

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Obama announced his latest strategy earlier this week to try to boost background checks for gun buyers, wiping away tears as he remembered the 20 children and six adults gunned down at an elementary school in Newtown, Connecticut, in December 2012.

"It continues to haunt me, it was one of the worst days of my presidency," Obama said on CNN.

'GUN LOBBY'S LIES'

Obama sought tougher laws after the Newtown massacre, but said he was foiled by the NRA.

He has made his changes using his executive powers, enraging Republicans who say he has overstepped his authority.

The White House has said the actions are lawful, although legal challenges are expected.

Obama, who will devote time this year to campaigning for Democrats running for November elections, vowed he would not campaign for any candidate who did not back gun reforms.

"All of us need to demand leaders brave enough to stand up to the gun lobby’s lies," Obama wrote in column in the New York Times that was published on Thursday.

He scoffed at the NRA for skipping the televised forum and said the White House had invited the group to meetings many times, to no avail.

"I'm happy to talk to them, but the conversation has to be based on facts and truth, and what we're actually proposing, not some ... imaginary fiction in which 'Obama's trying to take away your guns,'" Obama said.

Chris Cox, the NRA's chief lobbyist, said he was "not really interested" in talking to Obama.

"He doesn't support the individual right to own a firearm. That's been the position of his Supreme Court nominees, that's been the position of his administration," Cox said on Fox News after the CNN debate.

"So what are we going to talk about - basketball?"

(Reporting by Jeff Mason; Additional reporting by Eric Walsh; Writing by Roberta Rampton; Editing by Peter Cooney)