Independent Vermont Senator Bernie Sanders continues to make heads turn in his campaign for the Democratic presidential nomination for next year's White House race after overtaking former State Secretary Hillary Clinton.

The latest survey showed Sanders increasing his advantage over erstwhile frontrunner Clinton in the battleground states of Iowa and New Hampshire. The former Secretary of State, however, remains ahead in South Carolina.

A new CBS News/YouGov poll showed that in Iowa, Sanders got 43 percent support from likely Democratic caucus voters while Clinton had 33 percent. Sanders enjoys an even bigger lead over Clinton in New Hampshire—52 percent as against 30 percent among likely primary voters.

However, Clinton leads Sanders in South Carolina, getting 46 percent compared to Sanders' 23 percent.

CBS reported that Sanders is generating public enthusiasm while Clinton does not.

"Seventy-eight percent of Sanders voters in New Hampshire, and 63 percent of his voters in Iowa, say they enthusiastically support him, while just 39 percent of Clinton's backers in New Hampshire and 49 percent in Iowa say they enthusiastically support her," the report said.

Those who are propelling Sanders are the "very liberal Democrats," said CBS News Elections Director Anthony Salvanto on "Face the Nation" Sunday.

The poll also showed that the email controversy surrounding Clinton during her stint as US Secretary of State did not matter in the voters' choice of candidate.

Seven of 10 Democrats in the three states—74 percent in Iowa, 76 percent in New Hampshire and 75 percent in South Carolina—say the email issue does not matter to them.

In Iowa, 52 percent said Clinton's administration would favour the middle class, 24 percent the rich and 6 percent for the poor.

In contrast, under a Sanders administration, 43 percent said it would favour the middle class, 28 percent the poor and 4 percent the rich.

CBS News reported that in all three states, Sanders got strong support from independents who said they would vote in the Democratic primary.

Clinton is better among party loyalists. Among those who say they are Democrats, Sanders' lead is much smaller in Iowa and New Hampshire and Clinton is No. 1 in South Carolina.