Julián Castro raised $800,000 in the last 10 days of October, his campaign announced Friday, ensuring that he will stay in the race for the Democratic presidential nomination.

Castro, who had $670,000 cash on hand at the end of September, warned supporters last month that his campaign needed to raise the $800,000 by Oct. 31 or he would be forced to end his 2020 bid.

"Time and time again this campaign has defied expectations with the support of an army of dedicated, grassroots supporters," Castro's campaign manager Maya Rupert said in a statement. "We set an extremely ambitious goal to keep Secretary Castro's voice in this race, and our supporters met the challenge and delivered one of the best months of the campaign to date. We're not going anywhere – Julián will keep being a voice for the voiceless, and a champion for the Americans who have been left behind."

The campaign said it received more than $1 million during the month of October from nearly 50,000 donors and says it will now push forward with its sights set on the upcoming November and December Democratic primary debates. Castro has yet to reach the polling threshold required to qualify for the November debate and it's not clear if his campaign will continue if he does not make the debate stage.

Castro, the former Housing and Urban Development secretary under President Barack Obama, has pledged not to accept money from lobbyists or political action committees. His campaign made a frenzied appeal to supporters in the last few days of October and on Wednesday held a call-a-thon that it said brought in more than $100,000.

Though Castro has struggled to rise above 1% in national polls, he has endeared himself to progressives who see him as someone who is pushing the national debate on issues like immigration and criminal justice to the left.