Sen. Cory Booker, D-N.J., announced Monday he is dropping out of the Democratic presidential race.

With his departure, former Massachusetts Gov. Deval Patrick is now the only black candidate remaining in the 12 candidate Democratic primary.

"Nearly one year ago, I got in the race for president because I believed to my core that the answer to the common pain Americans are feeling right now, the answer to Donald Trump’s hatred and division, is to reignite our spirit of common purpose to take on our biggest challenges and build a more just and fair country for everyone," Booker said in an email to supporters obtained by NBC News. "I’ve always believed that. I still believe that. I’m proud I never compromised my faith in these principles during this campaign to score political points or tear down others."

"And maybe I’m stubborn, but I’ll never abandon my faith in what we can accomplish when we join together," he continued. "I will carry this fight forward — I just won’t be doing it as a candidate for president this year. Friend, it’s with a full heart that I share this news — I’ve made the decision to suspend my campaign for president."

Booker held a staff call at his campaign headquarters in Newark, New Jersey, before making his announcement public, a campaign official told NBC News.

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"It was a difficult decision to make, but I got in this race to win, and I’ve always said I wouldn’t continue if there was no longer a path to victory," he told supporters. "Our campaign has reached the point where we need more money to scale up and continue building a campaign that can win — money we don’t have, and money that is harder to raise because I won’t be on the next debate stage and because the urgent business of impeachment will rightly be keeping me in Washington."

Booker said he was "proud of the ideas" his campaign brought to the primary, including those on gun control and criminal justice reform.

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Booker polled at about 2 percent nationally, according to the RealClearPolitics polling average, and was knocked off the debate stage in recent months. Booker joins author Marianne Williamson and former Housing and Urban Development Secretary Julián Castro as candidates who have departed from the race this month.

Trump responded to Booker's departure, tweeting, "Really Big Breaking News (Kidding): Booker, who was in zero polling territory, just dropped out of the Democrat Presidential Primary Race."

"Now I can rest easy tonight," he added. "I was sooo concerned that I would someday have to go head to head with him!"

Booker's Democratic competitors offered gratitude for his candidacy in reacting to the news.

"Cory, you campaigned with joy and heart, and instead of just talking about bringing people together, you did it every day," former Vice President Joe Biden tweeted. "You made our politics better just by running. Grateful to you and looking forward to your continued leadership."

"Cory Booker — my friend, my brother," businessman Andrew Yang wrote. "Running alongside you has been one of the joyous parts of this race. You inspire me and millions of other Americans to be better and do better. I will miss seeing you and Rosario on the trail, but not for long. The fight continues." Yang was referring to Booker's girlfriend, actress Rosario Dawson.

Earlier this month, Booker said the president's looming impeachment trial, in addition to other matters in Washington, D.C., could deal a "big, big blow" to his presidential aspirations. In September, his campaign made a plea to supporters for donations, saying it would have no path forward if Booker did not quickly raise nearly $2 million.