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Sen. Elizabeth Warren, D-Mass., brushed off a tweet Thursday from President Donald Trump mocking her recent DNA test, telling reporters the president should spend "his time getting the government back open."

"We're now in the 13th day of the shutdown, we have hundreds of thousands of federal employees not getting their paychecks and work that's not being done all around this country," said Warren, who recently announced she is considering a run for the White House. "Those are the issues we need to worry about, and that's where we need to focus."

Trump, who has repeatedly called Warren "Pocahontas," posted an image mocking the results of a recent DNA test she took to show she does have distant Native American relatives.

Warren drew notice last year for her tough responses to Trump's attacks, but she ignored him in a video released Monday announcing she was forming an exploratory committee.

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Asked Thursday how she plans to navigate constant barbs from Trump, Warren pointed to the issues she wants to focus on in her potential bid for the presidency.

Trump "can bluster forever, but it doesn't change the underlying reality," Warren said. "Across this country wages are flat, across this country the cost of health care, the cost of sending your kids to college, the cost of housing, the cost of retirement are going up, up, up. Those are the things that matter to hard working families, and the reason that those things are happening are because of bad decisions being made right now in Washington."

In July, Trump challenged Warren at a Montana rally to take a DNA test, pledging to donate $1 million to charity if she took the test and "it shows you're an Indian."

"I have a feeling she will say no," he said.

After she took the DNA test and made the results public in October, Trump claimed he "didn't say" he would pay $1 million. "I didn't say that," Trump said. "You better read it again."

He then said he would make the payment only "if I can test her personally."

At an October rally for Republican Sen. Ted Cruz of Texas, Trump said that he couldn't call Warren Pocahontas anymore "because she has no Indian blood."

"She doesn't qualify," he said. "I said, 'I have more Indian blood than she has and I have none! I have none!'"