She raised about half of the latest amount — $6.5 million — through her digital program.

Bernie Sanders raised more than $25 million in the third quarter of the year, while Pete Buttigieg, the top fundraiser on the Democratic side from April through June, took in $19.1 million in the past three months.

Two others leading Harris in polls, Joe Biden and Elizabeth Warren, are also expected to outraise her.

Sen. Cory Booker of New Jersey, who threatened in recent days he'd have to suspend his campaign if things didn't turn around financially, raised more than $6 million in the third quarter, thanks to a late surge of $2.1 million from 46,000 donations.

Harris, who has struggled on the trail amid organizational challenges, is ramping up in Iowa as part of a plan to revitalize her bid. Her campaign said it would nearly double its number of organizers in Iowa in October and double number of its organizers in South Carolina by the end of November.

“As we have spent the summer months strengthening our infrastructure, we enter this final stretch of 2019 with ample resources to execute a winning game plan," Juan Rodriguez, Harris' campaign manager said in a statement.

"With hundreds of organizers and staff in the early states and Super Tuesday California, we are ready to harness the energy of our thousands of grassroots volunteers to phone bank, knock doors and turn out the vote for Kamala in these 2020 contests," Rodriguez added.