WASHINGTON -- President Barack Obama on Sunday declared that the Dec. 14 shooting massacre in Newtown "was the worst day of my presidency," and he sought to rally public support for lawmakers who will vote for tougher gun controls.

In an interview on NBC's "Meet the Press," Obama said "anybody who was up in Newtown ... understands that something fundamental in America has to change. And all of us have to do some soul searching, including me as president, that we allow a situation in which 20 precious small children are getting gunned down in a classroom."

Obama said the question is: "Are we going to be able to have a national conversation and move something through Congress? I'd like to get it done in the first year."

"This is not something that I will be putting off," Obama said, "and, yes, it's going to be hard" to get legislation through Congress.

He said he will put his "full weight" behind the recommendations of a task force on gun violence headed by Vice President Joe Biden. But ultimately, he said, it will be up to the American people.

"We're not going to get this done unless the American people decide this is important," he said.

Asked about the NRA's proposal that an armed guard be assigned to every school, Obama said he was skeptical that the only answer is putting more guns in schools, adding: "I think the vast majority of the American people are skeptical that this is going to solve the problem."