New York Mayor Michael Bloomberg (I) said Sunday that he remains optimistic about the prospects for new gun control measures coming from Congress, despite the recent news that an assault weapons ban wouldn't be part of the bill.

"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 said on NBC's "Meet the Press," adding: "I think we are going to win this. Celebrating in advance isn't the right thing to do. We've got to go out -- we've got a lot of work ahead of us."

Bloomberg acknowledged that the assault weapons ban faces an uncertain future, though, because the public isn't as united on that issue.

He said, however, that it was progress that Congress would vote on the ban as an amendment and he said he would continue to apply pressure. Bloomberg confirmed that he will spend $12 million in several states that are home to senators seen as swing votes in the gun debate.

"I don't think we should give up on the assault weapons ban," Bloomberg said. "But clearly it is a more difficult issue for a lot of people. I don't know that that reflects the NRA's power. It may be just that people have different views about assault weapons than they do about background checks."