Sen. Elizabeth Warren is planning a significant expansion of her presidential campaign, airing more ads and beefing up her staffing, a move that comes as the Massachusetts Democrat hopes to build on momentum that has placed her at or near the top of a growing number of polls.

Heading into the fall, Warren said she plans to roll out an “eight-figure” ad push in early primary states and to build on organizing efforts in later-voting states like Minnesota, Maine and California, according to an email sent to supporters Tuesday morning.

Warren — whose largest campaign expense so far has been staffing — will soon launch more than $10 million worth of digital and television ads in Iowa, New Hampshire, Nevada and South Carolina. Those are the first four states to cast votes in the upcoming primary season, making it critical for any candidate to have a good showing there.

Warren’s campaign declined to specify the spending breakdown between digital and television ads, but said the focus would be on digital first, with airtime reserved for television ads over the next few months. The ads focus on a familiar theme from Warren’s core message: that she’s not afraid to take on government corruption.

“It will be more digital than old-school broadcast television, and we have built an in-house staff to produce videos and ads rather than adopt the consultant-driven approach of other campaigns,” campaign manager Roger Lau said in the Tuesday email.

The foray into television advertising marks a shift for Warren, who eschewed TV ads in her 2018 reelection bid for the Senate. It reflects the challenge of running a nationwide presidential campaign, rather than focusing on a single state where the candidate is already well-known.

The announcement comes as Warren is moving toward the top of polls in Iowa and New Hampshire, though the race remains fluid. But her campaign is also seeking to show it’s building strength in states that are not in the first wave of primaries and caucuses.

State directors and organizers will be hired in places like Minnesota, Texas and Florida, the memo said, adding that the moves were designed in part to help Democrats win downballot races.

“We’re putting boots on the ground in places like Michigan and Minnesota, which will help flip state legislatures to Democratic control,” Lau wrote. “And we’re continuing to build the future of our party by investing in states like Texas and Florida.”

Warren has recently gained momentum in the packed Democratic primary field. Last week, she addressed her largest crowd yet — about 20,000 in Manhattan’s Washington Square Park — in a speech that hailed the political power of female-led organizing.

Last week, a poll from the Des Moines Register, CNN and Mediacom showed Warren about even with former vice president Joe Biden in Iowa, while a Monmouth University poll released Tuesday showed she had made significant gains in New Hampshire since May.

Annie Linskey contributed to this report.