The $12 million ad blitz targeting senators wavering on gun control will be just the beginning, Mayor Bloomberg warned Sunday.

“I have a responsibility ... to try to make this country safer,” Bloomberg said on “Meet the Press” when asked if he’d spend big-time in next year’s elections to target the National Rifle Association and members of Congress for opposing gun restrictions.

“If I can do that by spending some money, and taking the NRA from being the only voice to being one of the voices, so the public can really understand the issues, then I think my money will be well spent and I think I have an obligation to do that,” he said.