WASHINGTON (Xinhua) -- Julian Castro, the only Latino contender for the Democratic Party's nomination to challenge US President Donald Trump this election cycle, said Thursday that he is ending his campaign.

"It's with profound gratitude to all of our supporters that I suspend my campaign for president today," Castro tweeted.

"We've shaped the conversation on so many important issues in this race," he said in a video posted along with the tweet. "But with only a month until the Iowa caucuses and given the circumstances of this campaign season, I've determined that it simply isn't our time."

Castro, 45, formally launched his presidential campaign in January 2019.

A champion of progressive policies, the former housing secretary of the Obama administration and ex-San Antonio mayor has struggled with raising money and has not found his footing in polls.

In a tweet, former Vice President Joe Biden, the front-running Democratic candidate who worked with Castro in the Obama administration, praised him for using his platform "to lift the voices of others."

There are still 14 Democrats in the 2020 presidential primary field after Castro's exit.

According to the latest Economist/YouGov poll, Biden is leading the field comfortably at 29 percent, followed by senators Bernie Sanders and Elizabeth Warren, with 19 percent and 18 percent, respectively.

South Bend, Indiana Mayor Pete Buttigieg followed them at 8 percent, the poll showed. Senator Amy Klobuchar sat at 4 percent, while former New York City Mayor Michael Bloomberg, entrepreneur Andrew Yang and Congresswoman Tulsi Gabbard tied at 3 percent.