US Democratic Senator Elizabeth Warren has officially launched her bid for the 2020 presidency with a call to fight economic inequality and build “an America that works for everyone”.

Ms Warren delivered a sharp call for change at her presidential kick-off, decrying a “middle-class squeeze” that has left Americans crunched with “too little accountability for the rich, too little opportunity for everyone else”.

She and her backers hope that message can distinguish her in a crowded Democratic field and help her move past the controversy surrounding her past claims to Native American heritage.

Weaving specific policy prescriptions into her remarks, from Medicare for All to the elimination of Washington “lobbying as we know it”, Ms Warren avoided taking direct jabs at President Donald Trump.

Election 2020 WarrenElizabeth Warren takes to the stage during an event to formally launch her presidential campaign (Elise Amendola/AP)

She aimed for a broader institutional shift instead, urging supporters to choose “a government that makes different choices, choices that reflect our values”.

Mr Trump “is not the cause of what’s broken,” Ms Warren told an elated crowd in Lawrence, in her home state of Massachusetts, without using the president’s name.

“He’s just the latest – and most extreme – symptom of what’s gone wrong in America.”

In a tweet, Mr Trump referenced the controversy over her Native American identity, once again using the insulting nickname he has given her.

“Today Elizabeth Warren, sometimes referred to by me as Pocahontas, joined the race for President,” Mr Trump tweeted.

“Will she run as our first Native American presidential candidate, or has she decided that after 32 years, this is not playing so well anymore? See you on the campaign TRAIL, Liz!”

Asked to explain the tweet’s reference to “the campaign TRAIL”, the White House did not respond.

Supporters turned out in below-freezing temperatures, many hoisting signs — “Win With Warren,” one read.

A Massachusetts bakery created “Persist” cookies for the event to honour the candidate’s slogan, “Nevertheless, She Persisted,” words first spoken in the Senate to rebuke her.

Election 2020 WarrenElizabeth Warren during the event in Lawrence, Massachusetts (Elise Amendola/AP)

Asked if fellow New Englander Senator Bernie Sanders, a Vermont independent, could pose a serious threat to Ms Warren in New Hampshire’s critical primary should he get into the race, longtime backer Carlos Garcia said Ms Warren is “such an effective communicator that I think that people will respond to that very well”.

Ms Warren went straight from her kick-off to New Hampshire, home to the nation’s first primary, where her campaign projected that 350 people turned out for an event in the city of Dover.

She plans to spend Sunday in Iowa, where the lead-off caucuses will be the first test of candidates’ viability.

Ms Warren enters the race as one of the party’s most recognisable figures.

She has spent the past decade in the national spotlight, first emerging as a consumer activist during the financial crisis.

She later led the congressional panel that oversaw the 2008 financial industry bailout.

After Republicans blocked her from running the Consumer Financial Protection Bureau, an agency she helped create, she ran for the Senate in 2012 and unseated a Republican incumbent.