Bolstered by strong support from people of color and younger voters, Sen. Bernie Sanders is in a close second place behind former Vice President Joe Biden in the 2020 Democratic primary race, according to a new national poll published Monday morning.

The NPR/PBS NewsHour/Marist survey (pdf) found that Biden is leading the race at 24% support, followed by Sanders at 22%, Sen. Elizabeth Warren (D-Mass.) at 17%, and South Bend, Indiana Mayor Pete Buttigieg at 13%. No other Democratic presidential candidate broke the 10% mark.

"We're looking for late action, because it's so fluid," Lee Miringoff, director of the Marist Institute for Public Opinion, said of the primary race.

"I think we're looking at the last surge" for who could come out on top, Miringoff added.

According to the new poll, Sanders leads the Democratic presidential field among non-white voters (29% over Biden's 26%), voters under the age of 45 (37% to Warren's 18% and Biden's 14%), and progressives (29% to Warren's 23% and Biden's 17%).

The Vermont senator's lead among people of color "might be because of Sanders' strength with younger voters of color and Latinos," NPR reported Monday.

This portion of the poll was based on a survey of 704 Democrats and Democratic-leaning independents conducted from December 9 to 11. The margin of error is 5.4 percentage points.

The national poll is the latest of a number of strong polls for Sanders, which the senator's campaign and supporters have highlighted as evidence of a surge with less than two months to go until the 2020 Iowa caucuses.

In an op-ed for the New York Times last week, scholar and activist Keeanga-Yamahtta Taylor attributed Sanders' strength in the 2020 Democratic primary to his ability to activate a "multiracial working class" coalition with his bold economic policies.

"Mr. Sanders has reached the typically invisible, downwardly mobile working class with his language of 'class warfare,'" Taylor wrote. "He has tapped into the anger and bitterness coursing through the lives of regular people."