Pro-immigration reform conservatives use Rubio in new Fox News ad

The move comes following renewed signs of right-wing resistance to the bipartisan immigration bill working its way through the Senate, and seeks to undermine some conservative lawmakers' arguments that the bill would allow immigrants currently here illegally to access social welfare programs.

"Our current immigration system is a disaster. What we have now is de facto amnesty. There's no easy fix but there is a better way. Billions in new border security funding. Toughest enforcer measurements in history. No food stamps. No welfare. No ObamaCare," Rubio says in the ad. "They'll have to wait 13 years. They're going to have to pay fines. They're going to have to learn English. They're going to have to work. They're going to have to wait in the back of the line. It's not ideal, but it's tough and it's fair and it's enforceable. And that's exactly what we don't have now."

Rubio has been the leading advocate on the right for immigration reform, and remains by far the most powerful conservative voice fighting for the bill.

The group is spending $300,000 on the one-week ad buy, which is set to run through the Senate Judiciary Committee's markup of the bill next week. It's the latest in a series of major ad buys from conservative groups fighting for reform as they try to keep resistant Republicans from turning against the bill.