Ted Cruz is ramping up his appeal to voters as the strongest potential commander-in-chief in the GOP presidential field.

Facing the camera in a new TV ad, the Texas senator solemnly promises never to "apologize for America" after lamenting how unsafe the country has become under President Barack Obama and Hillary Clinton, the former secretary of state and current Democratic presidential frontrunner.

"We’ll rebuild our military. We’ll kill the terrorists. And every Islamic extremist will know, if you wage jihad against us, you’re signing your death warrant," Cruz says in the 30-second spot, titled "Dangerous."

Cruz is among the Republican candidates who have intensified their focus on national security following the recent Paris terrorist attacks and a shooting Wednesday in California that left 14 people dead. Addressing the Republican Jewish Coalition on Thursday, Cruz said he believes the United States "needs a wartime president to defend it."

The "Dangerous" spot comes as Cruz navigates an increasingly pitched battle over foreign policy with GOP rival Marco Rubio, who has said the Texan voted to "gut" U.S. intelligence capabilities earlier this year. One of the Florida senator's supporters is behind a TV ad airing in Iowa that says Cruz is responsible for weakening "America's ability to identify and hunt down terrorists."

The national security ad is one of two Cruz’s campaign released Saturday for the airwaves in Iowa, where he was completing a two-day swing through the first-in-the-country caucus state. Cruz’s campaign described the pair of TV spots as part of a two-week, six-figure media buy in the Hawkeye State that also includes digital and radio advertising.

The other TV ad, titled “Endorsement,” features U.S. Rep. Steve King of Iowa, an influential figure in conservative circles, making a hard pitch for Cruz to caucus-goers. King officially threw his support behind Cruz last month and has been stumping for him across the state since then.

“February 1st, do your duty for God and country, come to caucus and support Ted Cruz for President of the United States,” King says in the spot.

The two TV ads are set to first air Saturday during the Big Ten championship game between Iowa and Michigan State.

Their release comes roughly three weeks after the campaign launched its first major media buy in Iowa. That buy centered on a pair of TV spots that highlighted some of Cruz’s most well-received moments in the GOP debates so far.