Updated

Former New York Mayor Michael Bloomberg will spend $50 million this year to build a nationwide grassroots network on gun control in a direct challenge to the National Rifle Association, The New York Times reported.

The new lobbying group, called Everytown for Gun Safety, will encompass other gun control groups funded by Bloomberg, Mayors Against Illegal Guns and Moms Demand Action for Gun Sense in America, the report said.

Bloomberg told the Times the strategy will focus on expanding the background check system for gun buyers at the state and national levels. He made nearly $14 million in federal campaign contributions for gun-control candidates in the 2012 elections.

"They say, 'We don’t care. We’re going to go after you,'" he said of the NRA. "'If you don’t vote with us we’re going to go after your kids and your grandkids and your great-grandkids. And we’re never going to stop.'"

Separately, Bloomberg told NBC's "Today" on Wednesday that he has no plans to run for president in 2016, "plain and simple."

The 2012 shooting at Sandy Hook Elementary School in Connecticut —where a gunman used an assault rifle to kill 20 children and six others— led some cities and states to enact laws banning high-capacity magazines.

Bloomberg's group will target 15 states, including places where gun control laws have been implemented recently, and parts of the country seen as gun-friendly like Texas, Montana and Indiana, the Times reported.

Bloomberg said the organization will focus on women, especially mothers.

“You’ve got to work at it piece by piece,” he said. “One mom and another mom. You’ve got to wear them down until they finally say, ‘Enough.'"

Also planning campaign activity this year is Americans for Responsible Solutions, a gun-control group headed by former Rep. Gabrielle Giffords, D-Ariz., and her husband, ex-astronaut Mark Kelly.

The group reported late Tuesday that its political committee has raised nearly $14.5 million since it was founded in January 2013, and it plans to spend its money on federal and state races, said spokesman Mark Prentice.

Giffords was severely wounded in a Jan. 8, 2011, shooting rampage that killed six people and injured 13.

The National Rifle Association spent nearly $20 million on federal campaign activity in 2012 races. Its true strength, though, is viewed as its claimed 5 million members, many of whom consider gun issues strongly when voting.

The Associated Press contributed to this report.

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