Correction: This story incorrectly reported that the NRCC was also making a new investment in Wisconsin. It has since been updated.

The national GOP cavalry is having to ride into two more House districts once viewed as safe, the latest sign of an expanding House map that could benefit Democrats in the races’ closing week.

The National Republican Congressional Committee is dropping $600,000 to help Rep. Will Hurd (R-TX) and just short of $100,000 to help keep a Charleston, S.C.-based seat currently held by Rep. Mark Sanford (R-SC) in their column, sources tracking the buys tell TPM.

The moves are the latest GOP investments into districts party strategists had been confident just weeks ago that they would win. And like some other recent spending from the NRCC and the Congressional Leadership Fund, the GOP’s main House super PAC, they’ve been driven by Democratic candidates’ massive fundraising edges in both races.

The NRCC had pulled out of Hurd’s district after earlier spending, as he appeared to be safely ahead of Democrat Gina Ortiz Jones (D) at the time. But she has used a cash advantage to outspend him by a wide amount on the air in the race’s closing weeks, prompting the group to come back in to shore up his standing.

Republican Katie Arrington, who defeated Rep. Mark Sanford (R-SC) in a primary earlier this year, has raised $1.4 million total for the campaign, less than the $1.9 million pulled in by Democratic businessman Joe Cunningham. Cunningham has a $300,000 to $130,000 advantage in cash on hand as of Oct. 17.

Both of these races still lean to the GOP. But the NRCC, which has raised less money than the DCCC over the cycle, wouldn’t be spending in these districts if they weren’t concerned that they could slip away without some help.