(CNN) Sen. Elizabeth Warren raised more than $6 million for her presidential bid in the first quarter of 2019 and has $11.2 million in the bank, her campaign announced Wednesday, as advisers tell CNN that Warren is making huge hires in the early states and preparing for a slog to the 2020 Democratic convention.

In an email to supporters, Warren's campaign manager Roger Lau said that more than 135,000 donors made over 213,000 contributions in the first three months of the year, with an average donation of $28. A significant chunk of her total haul -- more than $1.4 million -- came in during the final week of the quarter when the campaign received over 50,000 new donations, Lau said. Warren transferred $10.4 million from her Senate campaign account, according to aides, and she spent $5.2 million -- most of what she raised -- in the first quarter.

Warren's fundraising haul falls well behind Vermont Sen. Bernie Sanders' $18.2 million, California Sen. Kamala Harris' $12 million, former Texas Rep. Beto O'Rourke's $9.4 million, and is also shy of the $7 million announced by South Bend, Indiana, Mayor Pete Buttigieg. Warren launched her exploratory committee on New Year's Eve and has had significantly more time than some of her competitors to raise cash, but her campaign has also not held a single fundraiser or solicited high-dollar checks.

The number of people that gave to Warren's campaign -- more than 135,000 -- is not far off from the 138,000 contributors touted by Harris and the 158,000 announced by Buttigieg. (All three candidates are eclipsed by Sanders on this front -- he said 525,000 donors gave to his campaign since he entered the race in February. O'Rourke's campaign has not revealed its number of donors.)

In conversations with CNN this week, Warren advisers painted a picture of a campaign that is laying the groundwork for a protracted battle for the Democratic nomination and anticipating the possibility that the Democratic contest turns into a 50-state scramble to pick up delegates. Warren has also focused heavily on ramping up operations on the ground, hiring scores of campaign staff and prioritizing human contact with voters in the field, aides said.

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