New York Mayor Michael Bloomberg said Sunday he will invest $12 million in a nationwide ad campaign to counter the powerful US gun lobby and rally support for background checks in gun sales.
"We're running ads around the country. We have people manning phone banks and calling. We're trying to do everything we can to impress upon the senators that this is what the survivors want," Bloomberg told NBC's "Meet the Press."
"I don't think there's ever been an issue where the public has spoken so clearly where Congress hasn't eventually understood and done the right thing."
Bloomberg declined to say whether he would directly target congressional candidates in the 2014 election, but said he would be spending $12 million on ads in around a dozen states.
"If 90 percent of the public wants something and their representatives vote against that, common sense says they are going to have a price to pay," Bloomberg said.
Wayne LaPierre, head of the powerful National Rifle Association, brushed off the billionaire mayor's plans, telling the same news program that his group's members had already mobilized to oppose new gun control legislation.
Bloomberg is "going to find out this is a country of the people, by the people, and for the people. And he can't spend enough of his $27 billion to try to impose his will on the American public," LaPierre said.
"We have people all over, millions of people, sending us $5, $10, $15 checks, saying stand up to this guy."
He said the NRA would support a better system of keeping records on the mentally ill and convicted criminals, as well as harsher penalties for individuals who use firearms to commit crimes.
The dueling interviews came 100 days after the Newtown school massacre, in which the killing of 20 children by a young man armed with an assault rifle reignited the country's gun control debate.
Bloomberg has said he will focus his campaign on legislation to expand background checks, which is seen as having a much better chance of succeeding than an outright ban on assault weapons or high-capacity magazines.
The Senate's top Democrat Harry Reid last week dropped a proposal to ban the sale of assault weapons, including the one used in the Sandy Hook killings, saying it had little chance of passing.
The Senate majority leader said he was instead introducing a bill with three other gun violence prevention measures, including a requirement for background checks for all gun sales, and would bring it to a vote in April.
Bloomberg, whose estimated $27 billion fortune makes him the seventh richest person in the United States, has made headlines recently for his proposals to curb sales of giant servings of soft drinks.