(Reuters) - A little-known mayor of a Miami suburb announced his bid to become president of the United States on Thursday, joining an already crowded field of Democratic candidates vying to become the party’s nominee in 2020.

Wayne Messam, 44, son of Jamaican immigrants, joins an unusually diverse slate of 15 other Democrats seeking to unseat President Donald Trump, the likely Republican nominee, in November 2020. The field includes the first openly gay candidate, six women, a Hispanic man and a Samoan-American congresswoman, among other minorities.

Messam defeated a 16-year incumbent in 2015 to become the first black mayor of Miramar, which has a population of about 122,000. He was re-elected in March.

In his campaign launch video, Messam jogs in sleek athletic gear through sugarcane fields, describing how he went to Florida State University on a football scholarship and played on the 1993 national championship team.

After college, Messam started a construction business with his wife.

“The lack of urgency to plan for the future and take action on the crises we can see coming is the biggest threat facing our nation,” he wrote on his campaign website.

Messam pledged to focus on reducing gun violence, mitigating climate change and reducing student loan debt and the cost of healthcare.

Messam is the second mayor to enter the Democratic race, joining Pete Buttigieg of South Bend, Indiana, population 101,000.

Vermont Senator Bernie Sanders, who came to national prominence when he ran for president in 2016, and former Vice President Joe Biden, who has yet to formally announce a run, are the front-runners in early polls.

The Democratic and Republican parties choose their candidates in state-by-state nominating contests that start in Iowa next February and culminate with party conventions the following summer.