A second US senator has announced her plans to join the race for the Democratic nomination in the 2020 US presidential election.
Kirsten Gillibrand, a senator for New York since 2009, will set up an exploratory committee - a key first step in a presidential bid.
The 52-year-old is the second Democrat from the Senate to announce such plans, joining Massachusetts' Elizabeth Warren.
Gillibrand - who worked as a corporate lawyer before entering politics - has been a fierce opponent of Donald Trump since he entered office.
Announcing her presidential plans, Senator Gillibrand argued: "I believe this country needs a movement rooted in compassion and courage. We want an America defined by strength of character, not weakness of ego.
"We need to protect our basic rights and fight for better health care, education and jobs. And I believe I'm the woman for the job."
She also announced she wouldn't accept contributions from corporate PACs (political action committees) or federal lobbyists, adding: "I'm not afraid to take on Trump, special interests or any powerful system – never have been."
Our movement is about lifting voices that have been ignored for too long. That means taking institutional racism and injustice head-on – in our politics, health care, education and economy. Let's show what we can build with determination and optimism, rather than hatred and fear.
— Kirsten Gillibrand (@SenGillibrand) January 15, 2019
Senator Gillibrand joins what's already growing into a crowded field of candidates - with several other senators such as Cory Booker and Kamala Harris widely expected to be preparing their own presidential bids.
Former housing secretary Julian Castro and congresswoman Tulsi Gabbard also announced their own campaigns last week.
Former vice president Joe Biden and independent senator Bernie Sanders are also potential candidates - although they have yet to reveal their intentions and are both in their mid to late 70s.
Beto O'Rourke - who ran an unsuccessful but surprisingly close campaign against Texas senator Ted Cruz last year - is also tipped as a possible contender to run against Donald Trump.
The race is likely to prove a battle between traditional Democrats such as Biden and a growing progressive movement represented by the likes of Sanders and Warren.
The race is getting underway with more than a year still to go until the first major primary vote in Iowa.
