Washington (CNN) The Democratic National Committee raised the fundraising and polling thresholds for the sixth Democratic debate on Friday, a move that could further reduce the size of the debates before primaries begin next year.

Democratic candidates, in order to qualify for the debate, will now need to receive 4% in at least four national or early state polls that meet the DNC's criteria or 6% in two early state polls. These polls must be released between October 16 and December 12.

Candidates will also have to have received donations from at least 200,000 unique donors, with a minimum of 800 from at least 20 different states. Like the polling threshold, candidate will have until December 12 to meet the fundraising threshold.

PBS NewsHour and Politico will co-host the debate on December 19 in Los Angeles.

These new thresholds are an increase to what candidates had to achieve before the Democratic National Committee's November debate : 3% in at least four DNC-approved polls of Democratic voters nationally (or at least 5% in two polls of the early-voting states) and donations from 165,000 separate donors -- including a minimum of 600 donors each in at least 20 states or territories.

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