Vermont Sen. Bernie Sanders has erased Secretary of State Hillary Clinton's wide lead for the Democratic presidential nomination since the start of year, putting the two in a dead heat nationally, a Reuters/Ipsos poll indicated Friday.

Clinton leads Sanders 48 percent to 45 percent among Democratic voters, according to the poll of 512 Americans, conducted Feb. 2-5 following the Iowa caucuses. The poll has a margin of error of 5 percentage points.

Democrats had been supporting Clinton by a more than 2-to-1 margin at the beginning of the year. Sanders has narrowed that lead considerably in the past several weeks.

clinton sanders Democratic U.S. presidential candidate and former Secretary of State Hillary Clinton and rival candidate U.S. Senator Bernie Sanders speak simultaneously at the NBC News - YouTube Democratic presidential candidates debate in Charleston, South Carolina Jan. 17, 2016. Photo: Randall Hill/Reuters

Clinton beat Sanders narrowly in the Iowa caucuses, the nation's first nomination contest ahead of the November election, but is expected to lose to him in New Hampshire. The two rivals clashed Thursday night in their first one-on-one debate, reflecting the tightness of the race.

There is still a wide gap between the two in name recognition nationally. Nearly a quarter of Democrats and two-fifths of independents say they are still not that familiar with Sanders. In comparison, Clinton has almost total name recognition among voters.

On the Republican side, Donald Trump continued to lead the field with 40 percent support. His level of support among Republicans was relatively unchanged following his second-place finish in the Iowa caucuses. Sen. Ted Cruz of Texas followed with 16 percent and Sen. Marco Rubio of Florida came in third with 13 percent.