WASHINGTON (Reuters) - The White House is weighing a far broader approach to curbing U.S. gun violence than just reinstating a ban on assault weapons and high-capacity magazines, the Washington Post reported on Sunday.

A working group led by Vice President Joseph Biden is seriously considering measures that would require universal background checks for gun buyers and track the movement and sale of weapons through a national database, the newspaper said.

The measures would also strengthen mental health checks and stiffen penalties for carrying guns near schools or giving them to minors, the Post said. The approach is backed by law enforcement leaders, it said.

President Barack Obama assigned Biden the job of designing the strategy after the massacre at a Newtown, Connecticut, elementary school last month that killed 20 children and six adults.

To sell such changes, the White House is developing strategies to work around the National Rifle Association (NRA), the powerful gun lobby.

They include rallying support from Wal-Mart Stores Inc and other gun retailers for measures that would benefit their businesses, the Post said.

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The White House has been in contact with advisers to New York Mayor Michael Bloomberg, a gun control advocate who could emerge as a surrogate for the administration's agenda, the paper said.

The Post cited several people involved in the administration's talks on gun control for its story. They included Dan Gross, president of the Brady Campaign to Prevent Gun Violence, and Chuck Wexler, executive director of the Police Executive Research Forum.

The White House had no immediate comment on the Post story. A White House spokesman told the newspaper that Biden's group was in the middle of its review and had not decided on its final recommendations.

The NRA has successfully lobbied federal lawmakers to stop major new gun restrictions since a 1994 assault weapons ban, which expired in 2004. The ban also prohibited ammunition magazines holding more than 10 rounds.

When asked if Congress will entertain new gun regulation, Senate Minority Leader Mitch McConnell said on NBC's "Meet the Press" that lawmakers needed to see Biden's recommendations.

"There will be plenty of time to take a look at their recommendations once they come forward," he said.

McConnell, a Kentucky Republican, said that for the next three months Washington's debates would center on federal spending and the rising debt.

Democratic Senator Heidi Heitkamp of North Dakota, an NRA member, said on ABC's "This Week with George Stephanopolous" that the reported proposals were "way in extreme" and would not pass.

In a statement, New York Democratic Senators Charles Schumer and Kirsten Gillibrand urged Biden to include in his proposals measures to prevent trafficking in illegal guns and to make it harder for felons and the mentally ill to get firearms.