Washington (CNN) Planned Parenthood will launch an ad campaign costing more than $1 million to pressure three vulnerable Republican senators for condoning the Trump administration's rule limiting abortion referrals.

The group announced a "seven-figure investment" on Thursday targeting Sens. Martha McSally of Arizona, Cory Gardner of Colorado and Thom Tillis of North Carolina. Each will face ads in their respective states.

The campaign addresses the federally-funded Title X family planning program, which provides resources including contraception, breast and cervical cancer screenings, and STD and HIV preventative education and testing. But the program does not include abortions. The television ads state that the senators have "let the Trump-Pence administration force Planned Parenthood out of Title X."

The Title X program serves about 4 million people a year, according to HHS. Planned Parenthood covers 40% of Title X's patients and has been involved with the program since it began, according to the organization. Critics say the "gag rule" would mostly affect communities of color, low-income people, the uninsured and rural residents.

Read More