WASHINGTON, Sept. 16 (Xinhua) -- Former U.S. Vice President Joe Biden keeps a double-digit lead over other Democratic contenders for the nation's presidency in 2020, according to a new poll released on Monday.

File photo: VCG

Biden was leading a shrinking Democratic field with 32 percent of the vote among Democratic primary voters surveyed, showed a Morning Consult poll.

Senator Bernie Sanders of Vermont finished the poll with 20 percent, while Senator Elizabeth Warren of Massachusetts was the third with 18 percent.

The three candidates are the only Democrats in the field that polled in double digits.

The latest results are based on 7,487 survey interviews conducted on Sept. 13-15.

The large, diverse Democratic field has been reduced from 27 to 20 and will likely continue to shrink as leading candidates continue to pull away in polls.

The party's fourth round primary debate will take place in Westerville, Ohio, next month.