Newt Gingrich picked up the support of Rep. Trent Franks (R-Ariz.) on Friday, while Rep. Tom Marino (R-Pa.) got behind Rick Santorum's presidential bid.

Franks becomes the eighth congressional endorsement for Gingrich, a former House Speaker, who has picked up the support of several House members who supported Mitt Romney in 2008. Marino is the third member of Congress to endorse Santorum, but none are members who served with Santorum when he was a senator. Marino is from Santorum's home state but didn't join the House until after Santorum had been defeated in the Senate.

"I share Rick Santorum's vision of lower taxes, less spending, private sector job creation, a strong national defense, and traditional family values," Marino said in a statement in which he called Santorum a longtime friend. "I believe that Rick Santorum offers our best hope of recapturing the White House and returning this nation to its prior position of strength and greatness."

Franks had already endorsed Michele Bachmann — her only congressional endorsement — but the Minnesota congresswoman dropped out of the race in early January, freeing up Franks to throw his support behind another candidate.

"While Newt's contrast with [President] Obama is clear, so is his contrast with other leading Republican contenders," Franks said. "As someone who believes that restoring constitutional protection to unborn children is a preeminent goal and responsibility for any administration, I believe that Mitt Romney would have an impossible time mobilizing pro-life voters if he became the nominee."