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Democratic Sen. Elizabeth Warren of Massachusetts responded Sunday to President Donald Trump's tweet a day earlier mocking her claims of Native American heritage. She suggested that the president may be in prison by the time the 2020 election rolls around.

At an Iowa rally on Sunday, Warren said Trump often posts tweets that are "racist" and "hateful."

"Here’s what bothers me, by the time we get to 2020, Donald Trump may not even be president," she said. "In fact, he may not even be a free person. But ... Donald Trump is not the only problem we’ve got."

Trump taunted Warren on Twitter after she announced her presidential bid at a large Massachusetts rally Saturday, asking if she will "run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore?"

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"See you on the campaign TRAIL, Liz!" he added. On Instagram, his eldest son, Donald Trump Jr., responded to the tweet by saying, "Savage!!! I love my president!"

Today Elizabeth Warren, sometimes referred to by me as Pocahontas, joined the race for President. Will she run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore? See you on the campaign TRAIL, Liz! — Donald J. Trump (@realDonaldTrump) February 9, 2019

The president's comment was seen by many as a reference to the Trail of Tears, the forced relocation of Native Americans in the mid-19th century from tribal lands, during which thousands died. The policy was pursued by the administration of Andrew Jackson, whom Trump has repeatedly praised as a great president.

Republican Rep. Liz Cheney of Wyoming brushed aside the tweet during an interview with CNN's "State of the Union" on Sunday, saying Warren has "made herself a laughingstock."

"I have concerns about somebody like Elizabeth Warren pretending to be a Native American," Cheney said, calling Warren's past assertions a "disgrace."

"I don't think anybody should be surprised that that is the reaction to her and her repeated claims," Cheney said, adding Warren is "somebody who can't be trusted."

CNN's Jake Tapper concluded the exchange by noting that Cheney did not directly address the content of Trump's tweet.

Earlier this year, Trump made a joking reference to the Wounded Knee massacre of Native Americans and the Battle of Little Bighorn to take a shot at Warren, whom he regularly refers to as "Pocahontas."

Warren has faced backlash and has apologized for claiming Native American ancestry in her past. She took a DNA test last year and revealed she was between 1/64 and 1/1024 Native American and has since apologized to Cherokee Nation leaders. Last week, The Washington Post reported that she listed her race as "American Indian" on a Texas State Bar registration card in 1986, which has renewed conservative mocking of her.