Barack Obama calls for tougher background checks for Americans buying guns

US President Barack Obama has called for tougher background checks on Americans trying to buy a gun as he and Republican challenger Mitt Romney engaged in their most extensive discussions on the gun control issue since last week's massacre in a Colorado theatre.

Their pointed comments revived a debate - if briefly - that has faded to the background in national politics and been virtually non-existent in this year's close presidential race.

Mr Romney said in a television interview that changing the nation's laws would not prevent gun-related tragedies. He mistakenly said many weapons used by the shooting suspect were obtained illegally. Authorities say the firearms used to kill 12 people and injure dozens were purchased legally.

In his speech to the National Urban League civil rights group, Mr Obama said he wanted a national consensus in the effort to stem gun violence.

Despite the Second Amendment's protection of gun rights, Mr Obama said, "I also believe that a lot of gun owners would agree that an AK-47 belongs in the hands of soldiers, not in the hands of criminals - that they belong on the battlefield of war, not on the streets of our cities."

Gun control is a hotly partisan issue in the US The powerful National Rifle Association, which fights gun control and has huge sway in Congress, has successfully made the issue nearly off limits among most legislators who fear the group's opposition at re-election time.

The Brady Campaign to Prevent Gun Violence challenged both Mr Obama and Mr Romney to lead a search for solutions to gun violence.

The group's president, Dan Gross, said it's shameful for leaders to play politics with the issue when lives could be saved.

The White House has faced fresh questions since the shootings about whether Mr Obama, a strong supporter of gun control while a senator from Illinois, would make an election-year push for stricter measures.

Mr Obama acknowledged a national pattern of failing to follow through on calls for tougher gun restrictions after violent crimes.

"Too often, those efforts are defeated by politics and by lobbying and eventually by the pull of our collective attention elsewhere," he said.

It's been more than a decade since gun control advocates had a realistic hope of getting the type of legislation they seek, despite predictions that each shocking outburst of violence would lead to action.

Mr Obama pledged to work with lawmakers of both parties to stop violence, including the steady drip of urban crime that has cost many young lives. That's an important issue to the black community, whose turnout in 2008 helped him win the White House.

The president called for stricter background checks for people who want to purchase guns and restrictions to keep mentally unbalanced individuals from buying weapons. Those steps "shouldn't be controversial, they should be common sense," he said.

Still, Mr Obama is unlikely to make a robust push for new gun control legislation while mired in a deadlocked campaign centred squarely on the economy.

Mr Romney, pressed on the gun control issue in an NBC news interview during a visit to London, said changing laws won't "make all bad things go away." He was meeting with Prime Minister David Cameron and attending the opening of the Olympic Games before heading to Israel and Poland.

Mr Romney was asked about his tenure as Massachusetts governor, when he signed a bill that banned some assault-style weapons like the type the Colorado shooter is alleged to have used. At the time, Romney described such guns as "instruments of destruction, with the sole purpose of hunting down and killing people."

Asked if he stood by those comments, Mr Romney mentioned the Massachusetts ban but said he didn't think current national laws needed to change.

"I don't happen to believe that America needs new gun laws. A lot of what this ... young man did was clearly against the law. But the fact that it was against the law did not prevent it from happening," he said.

AP