WATCH: Biden Not Surprised Sanders Tied With Clinton in Early States

'It's relatively new for Hillary to talk about wealth inequality. Hillary's focus has been other things, and that's been Bernie's. No one questions Bernie's authenticity on those issues.'

CNN

U.S. Vice President Joe Biden said he was not surprised that Democratic presidential candidate Bernie Sanders is "neck-and-neck" with Hillary Clinton in the early contests of Iowa and New Hampshire, saying the Vermont senator's message of income inequality is more authentic.

In an interview with CNN on Monday night, Biden said the focus by Sanders on the growing gap between the very rich and other Americans had struck a chord with voters, with some opinion polls showing him gaining ground.

"Bernie is speaking to a yearning that is deep and real, and he has credibility on it," Biden said. "And that is the absolute enormous concentration of wealth in a small group of people with the new class now being able to be shown being left out."

He added that Clinton had not focused on the issue as long.

"It's relatively new for Hillary to talk about that," Biden said. "Hillary's focus has been other things up to now, and that's been Bernie's. No one questions Bernie's authenticity on those issues."

On Tuesday morning, Biden told NBC's "Today" show that he was not trying to criticize Clinton, a former secretary of state, but that her focus had been on foreign policy, while income inequality had been Sanders' "mantra."

"Even when income inequality wasn’t as serious as it is today, it was his drumbeat,” Biden said. “She’s coming up with some very good ideas, but Bernie is pushing the envelope on this.”

The interviews came ahead of President Barack Obama's State of the Union address on Tuesday night

Clinton, who is campaigning in Iowa on Tuesday, is struggling to convert her large national lead in the polls to solid gains in the early primary states, which hold outsized influence on the election process.

Biden was heavily courted by some Democrats to mount a challenge to Clinton, but declined, citing family obligations after his son Beau Biden died of cancer last year. Within the party, concerns remain whether Clinton can overcome questions surrounding her use of personal email while secretary of state and a lack of enthusiasm among voters.

Biden also told CNN that he and Obama want to influence the presidential nominees in November's White House election, especially on gun control.

Clinton has increasingly criticized Sanders for past votes that were viewed favorably by the National Rifle Association.

Biden, when asked, said Sanders is making improvements to his position on gun control.

"What Bernie Sanders has to do is say that the Second Amendment says - which he has, of late - the Second Amendment says you can limit who can own a gun, that people who are criminals shouldn't have guns," Biden said. "People who are schizophrenic and have mental illnesses shouldn't own guns, and he has said that."