Julián Castro officially dropped from the presidential race on Thursday.

The former Secretary of Housing and Urban Development and Mayor of San Antonio announced his decision in a tweet: “It’s with profound gratitude to all of our supporters that I suspend my campaign for president today. I’m so proud of everything we’ve accomplished together. I’m going to keep fighting for an America where everyone counts—I hope you’ll join me in that fight.”

According to Breitbart News, Castro had spent about seven million dollars on his campaign.

Senator Corey Booker (D-NJ) expressed his appreciation for Castro, “I’m going to miss seeing my friend @JulianCastro on the trail. Thank you, Julián, for bringing your ideas and leadership to this race—your voice and campaign were invaluable in sticking up for underrepresented communities and pushing the field forward.”

Castro was thanked by Senator Bernie Sanders (I-VT), who wrote: “My deepest gratitude to you, @JulianCastro, for your tireless efforts to elevate all voices, shed light on the struggles everyday Americans face, and fight for a humane immigration system. I look forward to your continued leadership in the fight to transform our country.”

Senator Elizabeth Warren (D-MA) thanked Castro for “his powerful voice, proposing bold and progressive plans, and for using campaign to help people who need it now.”

“You made this race stronger and you will continue to be a leader in our party and our county for many years to come,” said Warren.

Joe Biden also praised Castro on Twitter in a post. “It was a privilege to work with @JulianCastro during the Obama Administration, and a true honor to be in this talented field of candidates with him. He led his historic campaign with grace and heart and used his platform to lift the voices of others. Thank you, Mr. Secretary,” wrote Biden.