A major anti-abortion group is trying to influence two key Senate races with a six-figure online ad buy in the final week of the election.

The Susan B. Anthony List said it is aiming to reach 550,000 abortion-opposing voters in Missouri and North Carolina who need to be persuaded to turn out on Election Day and vote for Republican Sens. Roy Blunt and Richard Burr, who are in tough battles for their seats. The group wouldn’t disclose how much it is spending on the ad buy beyond “six figures.”