The Senate race between Sen. Scott Brown (R-Mass.) and Democrat Elizabeth WarrenElizabeth Ann Warren2020 Dems slam Trump over Putin presser Senate Dems rip Trump after Putin news conference Sanders: Trump should confront Putin over Mueller probe indictments MORE will go down to the wire, according to a new poll.

Warren leads Brown 43 percent to 41 percent in a survey by the nonpartisan MassINC Polling Group released Thursday — within the margin of error.

The poll was taken in late April — before the emergence of a controversy over Warren's claim to Native American heritage and whether she used that claim to further her career.

Brown's favorability rating stands at 46 percent, compared to 34 percent for Warren. Among Republicans, 73 percent view Brown favorably.

But the Democrat, who has not held elected office, has more room to grow. Seventeen percent of voters are still unfamiliar with Warren.

Brown runs the strongest in Boston's outer suburbs, where 56 percent view him favorably, compared to 40 percent for Warren.

The close state of the race suggest Brown's and Warren's increasingly harsh attacks on one another are either canceling each other out or having little effect.

On Thursday, the day after President Obama declared his support for gay marriage, the Massachusetts Democratic Party dispatched local allies to knock Brown for what they deemed an "anti-equality record."

Brown is opposed to gay marriage, but has called the issue "settled law" in Massachusetts, where it is legal. Brown also opposed non-discrimination legislation sought by gay rights activists, but he supported the repeal of the military's ban on gays serving openly — one of the only Republicans to break ranks on that issue.

Massachusetts Republicans, meanwhile, released a web video entitled "Fraudster" splicing news reports critical of Warren and her handling of the issue of her Native American heritage. The video also showed clips of Warren's responses to the issue that failed to put to bed questions about whether she claimed Native American heritage when applying for teaching positions.

“This story is not about whether Elizabeth Warren is a Native American, what it is about, is undermining Warren’s credibility and competence as a candidate," one reporter says in the video.

The poll of 438 registered voters was conducted April 25-28 and had a margin of error of plus or minus 4.7 percentage points.