MIAMI, United States, June 27 (Xinhua) -- The second night of the first Democratic primary debate here on Thursday featured more early front-runners for the party's presidential nomination to challenge President Donald Trump in 2020.

Democratic US 2020 election presidential candidates  debate during the second night of the first Democratic presidential candidates debate in Miami, Florida, US June 27, 2019. (Photo: VCG)

Thursday night's 10-Democrat matchup included four of the five front-running candidates in early polls: former Vice President Joe Biden, Senator Bernie Sanders of Vermont, Senator Kamala Harris of California, and South Bend Mayor Pete Buttigieg of Indiana.

They shared the stage with Senator Michael Bennet of Colorado, Senator Kirsten Gillibrand of New York, former Colorado Governor John Hickenlooper, Congressman Eric Swalwell of California, author and activist Marianne Williamson, and entrepreneur Andrew Yang.

Debate moderators are expected to raise such topics as economy, healthcare, education, immigration, climate change, and foreign policy, similar to those for the first group of participants on Wednesday night.

According to debate rules, each candidate will have 60 seconds to answer questions and 30 seconds for rebuttals. There are no opening statements, but each candidate will have one minute for a closing statement.

Wednesday's debate was attended by Senator Elizabeth Warren of Massachusetts, another top-tier contender, along with former Congressman Beto O'Rourke of Texas, Senator Cory Booker of New Jersey, New York Mayor Bill de Blasio, Washington Governor Jay Inslee, and five others.

Together, 20 candidates qualified for the first primary debate for either scoring at least 1 percent support in three qualifying polls or receiving donations from at least 65,000 unique donors.

The two-night debate, hosted by NBC News, MSNBC and Telemundo at Miami's Adrienne Arsht Center for the Performing Arts, was the first of a dozen that the Democratic National Committee had planned for the party's primary.

The second debate is scheduled for July 30-31 in Detroit, Michigan.