“I have decided to run and will be making a formal announcement within the next week,” Ms Gabbard, an Iraq War veteran as well as the first Hindu and first Samoan-American elected to congress, told CNN.
In recent months, the 37-year-old has paid visits New Hampshire and Iowa, the first states to hold primaries, and has written a memoir due to be published in May.
In an interview due to be broadcast over the weekend, the congresswoman, who first elected to represent Hawaii’s 2nd congressional district in 2012, says: “There are a lot of reasons for me to make this decision. There are a lot of challenges that are facing the American people that I’m concerned about and that I want to help solve.”
She adds: “There is one main issue that is central to the rest, and that is the issue of war and peace. I look forward to being able to get into this and to talk about it in depth when we make our announcement.”
In 2016, Ms Gabbard was one of the most prominent politicians to back Bernie Sanders over Hillary Clinton in the 2016 Democratic primary. She quit her position as vice chair of the Democratic National Committee in order to make the endorsement.
Asked last year whether she would still consider running if Mr Sanders ran, Ms Gabbard said Mr Sanders was a friend and she did not know what his plans were.
“I’m thinking through how I can best be of service and I’ll make my decision based on that,” she said.
She she has faced criticism for travelling to Syria and meeting with President Bashar Assad, who has been accused of war crimes.
She said it was important to meet with adversaries if “you are serious about pursuing peace”, the Associated Press said.
Senator Elizabeth Warren of Massachusetts on December 31 announced she had formed an exploratory committee for a presidential run – the most high profile Democrat to do so. She has also made visits to Iowa and New Hampshire.