Vice President Joe Biden “guaranteed” Mayor Thomas M. Menino — a leading national gun control advocate — that President Obama will pass sweeping firearms reforms by the end of the month, the mayor said today.

“He said, ‘Tommy, I guarantee you, we’ll get it done by the end of January,’” Menino said at City Hall today. “They’re going to get it done.”

The mayor, who has been recovering from a host of ailments for the past two months, said Biden called him several times while he was in the hospital, including a call after the Newtown school massacre to discuss gun control.

Menino and New York Mayor Michael Bloomberg co-chair the 500-mayor-strong Mayors Against Illegal Guns and have called for national gun reform in the wake of last month’s Sandy Hook school killings.

“I understand the second amendment, the right to bear arms. But I don’t understand how young kids should be able to get guns,” he said, referring to the plague of urban gang violence largely involving young males.

Menino added that the president has “no excuse not to pass strong (gun reform) legislation,” since he is in his last term and doesn’t have to worry about angering pro-gun voters or the National Rifle Association.

“It’s time to get this moving and moving quickly,” Menino said. “Let’s do it now.”

In a wide-ranging interview, Menino also said he’s “feeling better than I have in nine months” and hinted he could seek an unprecedented sixth term.

“I still have the energy,” he said. “I still have a lot more things I want to accomplish . . . If I believe I can make a difference in this city and move this city forward, that’s my future.”

Menino was hospitalized in October and spent nearly two months in the hospital and a rehabilitation clinic. He’s still having difficulty walking but is in daily physical therapy.

He’s staying at the Parkman House, because it has elevators, but said he “can’t wait” to get back to living at his Hyde Park home. He said he’s also looking forward to getting back to a regular schedule, but may scale back his public appearances slightly.

“You can’t stop being who you are,” he said. “Once you stop being who you are, that’s when you get in trouble. I’m not going to stop being Tom Menino.”