Republican presidential candidate Marco Rubio fired back at fellow 2016 hopeful Jeb Bush, calling him "desperate" in a new campaign ad that focuses on national security and immigration.

In a new 30-second ad released Friday, the Florida senator retaliated against an ad that Bush's super PAC aired on Monday that pokes fun of his controversial high-heeled boots while claiming he has flipped flopped on issues like immigration and Syria. The Right to Rise ad, which ran on air in Iowa and South Carolina, cost almost $3 million, reports Politico.

In response, Rubio says desperation has led Bush to spend big bucks on false attack ads.

"We all see what's happening. Jeb Bush is desperate and spending millions on false attacks," says Rubio in the ad, which is titled "Happening."

He goes on to promise to reverse President Barack Obama's executive action on immigration and build a wall on the U.S.-Mexico border.

"When I'm president, there will be no amnesty. I'll cancel Obama's unconstitutional executive orders; cut sanctuary city funding; and deport criminal aliens," Rubio says in the video, which will air in Iowa.

"We'll add 20,000 border agents; finish all 700 miles of border wall; and if we aren't 100 percent sure who you are and why you're coming to America, you're not getting in," he adds.

More than likely, it's this type of anti-immigrant sentiment that will hurt Rubio's chance of winning over Latino voters should he become the Republican presidential nominee. According to an NBC/Wall Street Journal poll released last month, Rubio has about 36 percent of the Hispanic vote compared to Democratic front-runner Hillary Clinton, who has 59 percent.

In addition, the Rubio campaign published a second new ad entitled "Support" that features Kelly Terry-Willis, the sister of slain Border Patrol agent Brian Terry. In the ad, she talks about her brother's death on the Mexican border in 2010, which exposed the Fast and Furious operation -- in which the U.S. government sanctioned illegal straw purchases in order to track the guns back to Mexican criminal leaders.

"My brother, Brian, sacrificed his life while serving along a southern border that has grown out-of-control with an administration that has done nothing to change it," says Terry-Willis.

"I know and trust that with Marco we will finally secure our border, and ensure that the men and women who served alongside Brian have the support from Washington they need."

Watch the ads below.

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