President Obama's former campaign manager on Monday sharply criticized Massachusetts Democratic Sen. Elizabeth Warren for releasing the results of a disputed DNA test that she said backed up her claims of Native American ancestry. He claimed she was throwing her party off-message just weeks before November's critical midterm elections.

"Argue the substance all you want, but why 22 days before a crucial election where we MUST win house and senate to save America, why did @SenWarren have to do her announcement now?" former President Barack Obama's 2012 campaign manager, Jim Messina, tweeted.

"Why can’t Dems ever stay focused???" added Messina, who also served as deputy White House chief of staff.

Warren, considered a likely 2020 presidential contender, is an overwhelming favorite to win re-election in Massachusetts in November.

When her claims of Native American heritage first became a widely publicized issue during her tight 2012 Senate campaign against then-incumbent Republican Sen. Scott Brown, polls showed most voters in the state didn't care.

MSNBC anchor Craig Melvin also panned Warren's decision to release her DNA results on-air Monday, during an interview with Boston Globe reporter Annie Linskey. The Globe first reported the results of the analysis into Warren's bloodline.

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“Did [Warren] gain anything by putting out the DNA test results?" Melvin asked. "The best I can gather, according to your paper’s reporting, she’s 1/1000th — something like that — I think I might be just as Native American as she is.”

“I don’t know who my great great great great grandmother or grandfather is," Linksey responded, noting that Warren's claimed heritage was "pretty far back" in her genetic line.

Meanwhile, New York Times reporter Nick Confessore wrote sarcastically on Twitter, "President Trump is sure to stop mocking Senator Warren about her ancestry now that she has provided definitive proof."

And Matthew Breen, LogoTV's editorial director, openly wondered if Warren was engaging in an "unserious distraction from a concerted midterm Dem strategy" -- or something more clever.

President Trump repeatedly has derided Warren for claiming she has Native American ancestry. At a rally in July, he joked that he would pull out a heritage kit during a hypothetical presidential debate with Warren and slowly toss it at her, "hoping it doesn't hit her and injure her arm, even though it only weighs probably two ounces."

Trump said he would offer to donate $1 million to Warren's preferred charity if she took the ancestry test and it proved she is Native American. Asked about that Monday afternoon, Trump said that Warren "owes the country an apology" and asked reporters, "What's her percentage? One-one-thousandth?"

He added that he would only give her charity $1 million if he is allowed to conduct the DNA test personally.

"I'll only do it if I can test her personally, OK? That will not be something I enjoy doing either," Trump said.

The test results Warren publicized did not definitively prove she has significant Native American ancestry, even though Stanford professor Carlos D. Bustamante, who conducted the analysis, said the results "strongly support the existence of an unadmixed Native American ancestor."

"I think I might be just as Native American as she is." — MSNBC anchor Craig Melvin

According to the analysis Warren took, “the vast majority” of Warren’s family tree is European and there is “strong evidence” she has Native-American ancestry “in the range of 6-10 generations ago.”

As reported by the Globe, this means she could be between 1/64 and 1/1,024 Native American (though the newspaper initially published an erroneous figure and had to correct it).

Republicans countered that having such a trace amount of Native-American heritage does not give Warren “the right to claim minority status” -- as she was accused of doing to advance her career at Harvard Law School years ago.

Warren repeatedly claimed to be Native American throughout her academic career, and a Fordham Law Review article at the time of her hiring described her as the faculty's "first woman of color." The Boston Globe has claimed that Harvard did not consider her ancestry as a factor in her hiring.

“Warren might even be less Native American than the average European American,” Republican National Committee spokesman Mike Reed said in a statement Monday. He also cited a 2014 study that cast doubt on Warren's claim.

The study, published by a team of scientists in late 2014 and featured in The New York Times, amounted to the largest-ever genetic profile of the U.S., based on 160,000 people. The study examined the average Native-American ancestry for Americans—including European, African and Latino Americans.

According to the Times report on the study, which can be found on the National Institutes of Health website, “European-Americans had genomes that were on average 98.6 percent European, .19 percent African, and .18 percent Native American.” That would potentially mean Warren has less Native American DNA than the average American.

Additonally, the analysis Warren used didn't rely on Native American DNA, calling into question its reliability.

"To make up for the dearth of Native American DNA, Bustamante used samples from Mexico, Peru, and Colombia to stand in for Native American," the Globe admitted.

Still, Warren appeared intent on pushing the results of the test on Monday.

"By the way, @realDonaldTrump: Remember saying on 7/5 that you’d give $1M to a charity of my choice if my DNA showed Native American ancestry?" she wrote. "I remember – and here's the verdict. Please send the check to the National Indigenous Women’s Resource Center: http://www.niwrc.org/donate-niwrc."

Fox News' Brooke Singman contributed to this report.