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Poll: Donald Trump leads in three early states; Hillary Clinton, Bernie Sanders in close race

Last Updated Jan 28, 2016 10:16 AM EST

Just four days until the Iowa caucuses, Donald Trump is overtaking Ted Cruz in the kickoff state, and among Democrats, Hillary Clinton has a slight advantage over rival Bernie Sanders, according to new polls of three early-nominating states released Thursday.

A survey conducted by NBC News/Wall Street Journal/Marist among likely Iowa caucus-goers shows Clinton with 48 percent support and Sanders at 45 percent -- a lead within the poll's margin of error of 4.7 percent. Former Maryland Gov. Martin O'Malley garners just three percent.

Trump, who officially announced Wednesday that he would not participate in the last GOP debate before the Iowa nominating contest, has leapfrogged over Cruz in the state where residents will caucus on Feb. 1. Trump, who trailed Cruz by four points in the same poll conducted in early January, now leads the Texas senator 32 percent to 25 percent. Florida Sen. Marco Rubio comes in third with 18 percent of support, while retired Ben Carson has eight percent and former Florida Gov. Jeb Bush has four percent. No other candidates reach more than two percent in the poll.

In New Hampshire, Sanders has put a wide margin between himself and Clinton. When the poll was conducted in early January, Sanders had a four-point lead over his rival, 50 percent to 46 percent. Now, the Vermont senator has pulled ahead to a 20-point advantage over Clinton, 57 percent to 38 percent.

Among likely Republican primary voters in New Hampshire, the survey shows Trump with a commanding lead over Cruz, his closest rival. Trump garners 31 percent of support to Cruz's 12 percent. The margin is virtually unchanged since the poll was last conducted. Rubio and Kasich tie for third with 11 percent support. Bush comes in fourth with eight percent, and Christie trails closely behind with seven percent. No other contender in the GOP race attracts more than five percent support.

In South Carolina, Trump continues his strong showing, with 36 percent. Cruz again finishes second at 20 percent, with Rubio in third at 14 percent. Bush takes in nine percent, Carson eight percent.

Among likely Democratic primary voters in South Carolina, Clinton leads with more than double Sanders' numbers. Sixty-four percent back the former secretary of state, while 27 percent back Sanders. O'Malley sits at two percent in the poll. Seven percent say they are still undecided about who to support in the race.

Clinton's lead in South Carolina is powered by her support among African Americans. Among likely African American voters, 74 percent back Clinton, compared to the 17 percent that support Sanders.