WASHINGTON (Reuters) - The Democratic National Committee on Monday announced new criteria for the fifth presidential debate in November, requiring candidates to meet one of two polling requirements and have 165,000 unique donors.

FILE PHOTO: Former Vice President Joe Biden speaks as South Bend Mayor Pete Buttigieg, Senator Bernie Sanders, Senator Elizabeth Warren and Senator Kamala Harris listen during the 2020 Democratic U.S. presidential debate in Houston, Texas, U.S., September 12, 2019. REUTERS/Mike Blake/File Photo

Candidates must either receive 3 percent or more support in four national or early state polls or 5 percent or more support in two polls of the states that hold early presidential nominating contests: Iowa, New Hampshire, South Carolina or Nevada.

They must show a minimum of 600 unique donors per state in at least 20 U.S. states, territories or the District of Columbia, the DNC said.

The new requirements promise to further cull the large Democratic field of 19 candidates seeking to challenge Republican President Donald Trump in the November 2020 election. Former Vice President Joe Biden has led most opinion polls so far, followed by U.S. Senators Elizabeth Warren and Bernie Sanders.

The sprawling field has made it difficult for lesser-known candidates to register in the minds of Democratic voters, with several polling at 1 percent or less nationally.

New York Mayor Bill de Blasio ended his 2020 bid on Friday, saying the party’s rules for qualifying for televised debates had made it hard for him to continue. He failed to qualify for a Sept. 12 debate that featured the 10 leading candidates for the party’s nomination.

Criteria for the September and October debates required donations from at least 130,000 people and support of at least 2% in four DNC-approved polls.

U.S. Senator Cory Booker of New Jersey will drop out of the running unless he can raise $1.7 million over the next 10 days left in the fundraising quarter, his campaign said on Saturday.

“If we don’t have the money to grow, we are not going to stay competitive in this race,” Booker told MSNBC on Monday. “I don’t want to stick around if I’m not in this to win it.”

The next debate will be held in Westerville, Ohio, on Oct. 15 and possibly Oct. 16, depending on the number of qualifying candidates.

(The story corrects first two paragraphs to show candidates must hit either polling threshold, not both, to qualify)