Lincoln Chafee, a former independent governor and Republican senator from Rhode Island, said he is running for the Democratic nomination for president.
His made the statement Thursday on CNN, one week after he announced he had formed an exploratory committee.
“Yes, that's why I'm running. Because I feel strong about where we're going as a country," Chafee told CNN, when asked why he's been so critical of Hillary Clinton, the only Democrat to formally declare for 2016.
But Chafee spokeswoman Debbie Rich told CNN that Chafee did not formally declare himself as a candidate for president, despite saying "I'm running."
"We are still in the exploratory committee phase," she said. "We will file the proper papers to be an official candidate, but that has not happened yet."
Chafee also told CNN, "There's no doubt I'm the underdog."
Other Democrats that could challenge Clinton for the Democratic nomination include former Virginia Sen. Jim Webb, former Maryland Gov. Martin O'Malley and Vermont Sen. Bernie Sanders. Vice President Joe Biden has not yet ruled out a run.
Last weekend, Chafee was critical of Clinton’s vote on the Iraq war in 2002. As a GOP senator, he voted against it.
"That was a moment where the premise for going to Iraq was so false that there were weapons of mass destruction, she didn't do her homework. We live with the ramifications," Chafee told CNN’s “State of the Union.” "You may say that's 12 years ago -- that's a big motivator for me running. If you show a lack of judgment, lack of doing homework then, what can we expect in the future?"