Sen. Ted Cruz (Texas) on Thursday fired back at Republican presidential rival Sen. Marco Rubio (Fla.) over the issue of national security. 

“Look, I think it's a lot of silliness,” Cruz chuckled when asked on conservative radio host Glenn Beck's program about the charge that he voted to degrade U.S. national security. 

“In many ways, it's a backhanded compliment,” Cruz said, referring to Republican rivals targeting him. “If they're not shooting at you, you're not doing much of anything.”

Rubio this week stepped up his attacks on Cruz, accusing him of hurting the military and weakening U.S. intelligence capabilities. 
Rubio said on Hugh Hewitt's radio program Wednesday that Cruz “is someone I like personally,” but added, “on some of the defense issues, we've parted ways.”

Cruz “voted for budgets that have hurt the military” and “voted for a budget that basically gutted our foreign aid program, particularly our defense of the Israelis and the aid that we’ve provided them,” Rubio said. “And he was a part of that coalition that worked with the Democrats like Chuck Schumer and the ACLU to harm our intelligence programs.”

Cruz shot back on Thursday, saying on Beck's show, “I understand Marco's campaign's desire, desperate desire, to change the topic from Marco's longtime partnership with Chuck Schumer and Barack Obama to push a massive amnesty program.”

“Particularly, in light of the Paris attacks, a lot of people are wondering, well gosh, why would he have supported the Democrats in granting citizenship to 12 million people here illegally and not securing our border, and opening up our refugee program so more and more potential terrorists could come into this country?” Cruz asked. 

The pair have sparred since last week's GOP debate. Rubio's campaign has focused on Cruz's support for the USA Freedom Act, which banned the bulk collection of American's phone data. Cruz said Thursday that the law “also had vigorous tools to go after terrorists.”