Poll: Clinton, Sanders neck-and-neck in Iowa, NH
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Sen. Bernie SandersBernie SandersSunday shows preview: Aftermath of failed healthcare bill Michael Moore warns Dems: Now is not the time to gloat Warren: 'Today is a great day... but I'm not doing a touchdown dance' MORE (I-Vt.) has maintained his lead over Democratic presidential front-runner Hillary ClintonHillary Rodham ClintonDemocrats step up calls that Russian hack was act of war Comet Ping Pong shooter pleads guilty Time for 'J. Edgar' Comey to take his leave MORE in New Hampshire and pulled to within the margin of error of her in Iowa, a new poll finds.

According to a NBC News-Wall Street Journal-Marist survey released on Sunday, Clinton has only a 3-point lead over Sanders in Iowa, well within the poll’s 4.8 percentage point margin of error. Clinton takes 48 percent support in the Hawkeye State, compared to 45 percent for Sanders.

That’s a much closer race in Iowa than other recent polls have found. According to the RealClearPolitics average of surveys, Clinton leads by 12.5 points in Iowa.

New Hampshire has long been a more competitive race between the two, and here the poll found Sanders leading with 50 percent of the support over Clinton at 46, in-line with other recent polling. According to the RCP average, Sanders leads by 5.3 points in the Granite State.

The Sanders campaign has been seeking to draw attention to polling that finds the Vermont senator performing better than Clinton in head-to-head match-ups against Republicans in the general election, and the NBC survey confirmed those claims.

Sanders leads GOP front-runner Donald TrumpDonald TrumpFormer US envoy: No good military options against North Korea Trump official and TV surrogate leaving White House: reports Biden: I regret not being president MORE head-to-head by 13 in Iowa, while Clinton only leads him by 8. In New Hampshire the disparity is even greater, with Sanders leading Trump by 19, and Clinton only edging him by 1.

The poll produced similar findings in head-to-head match-ups against Sens. Ted CruzTed CruzHow 'Big Pharma' stifles pharmaceutical innovation AIPAC must reach out to President Trump Under pressure, Dems hold back Gorsuch support MORE (R-Texas) and Marco RubioMarco RubioSenators introduce new Iran sanctions Senate intel panel has not seen Nunes surveillance documents: lawmakers With no emerging leaders, no clear message, Democrats flounder MORE (R-Fla.).

The most stunning finding was in New Hampshire, where Rubio leads Clinton 12, but trails Sanders by 9.

Sanders is buoyed in the head-to-head match-ups with Republicans by his strength among independents.

The survey of 2,821 registered voters in Iowa has a 1.8 percentage point margin of error. The survey of 1,888 registered voters in New Hampshire has a 2.3 percentage point margin of error. The surveys of 422 likely Democratic caucus-goers in Iowa and 425 likely Democratic primary voters in New Hampshire have 4.8 percentage point margins of error.