WASHINGTON (AP) — U.S. Sen. Cory Booker is running for president in 2020.

The New Jersey Democrat made the announcement Friday in a video message to supporters, emphasizing a return to American unity in an era of deep political divisions.

Booker enters a crowded presidential primary field that includes three of his fellow senators and could soon include three more. The 49-year-old visited Iowa and New Hampshire in October, an early indication of his intentions to challenge President Donald Trump.

Booker is a former Newark mayor. He won a special election to the Senate in 2013 and won a full term in 2014. He will be able to run for a second Senate term in 2020 as well as run for president thanks to a law that New Jersey's governor signed in November.