Donald Trump, front-runner for the 2016 Republican presidential nomination, said he has to maintain his tough talk on Muslims, despite the use of his comments in a recruitment video from the Somali extremist group al-Shabab.

In a wide-ranging interview on CBS's Face the Nation on Sunday, Trump also said the U.S. should focus more on mental health measures to curb gun violence, such as building "institutions for people that are sickos."

"They use other people, too," the billionaire real estate mogul said  of the Somali video, which was posted on Twitter on Dec. 31. "What am I going to do? I have to say what I have to say.''

Trump has called for "a total and complete shutdown of Muslims entering the United States." A clip of him proposing the temporary ban appeared in a 51-minute video produced by the group, which has ties to Islamic State and al-Qaeda. 

A top aide to President Barack Obama said on Saturday that "nobody should be surprised" that al-Shabab had used Trump's comments.

"We have said now for weeks, if not months, that any indication that supports the notion that the United States is at war with Islam will be taken advantage of by terrorist organizations who depend on propagating that narrative to recruit people," Ben Rhodes, deputy national security adviser, said in a briefing with reporters in Honolulu.

"Clearly we need to defeat terrorists we need to kill terrorists on the battlefield. We also need to defeat this narrative that allows them to recruit people," Rhodes said.

On ABC'S This Week broadcast on Sunday, Ben Carson, another 2016 Republican presidential hopeful, didn't see a need for Trump and others to tone down their comments.

"The fact of the matter is, let's not get so concerned about how offended our enemies are," said Carson, a retired neurosurgeon.

Trump, who has relied on free media appearances for exposure rather than purchasing advertising, also said on Sunday that he would begin a dramatic escalation in ad spending as the first nominating contests for 2015, in Iowa and New Hampshire, approach. 

"I'm going to spend $2 million on ads per week at least," he said during the interview, which was filmed on Dec. 31.

Trump also repeated his condemnations of the executive actions that President Obama is considering to attempt to curb gun violence.

"I don't like anything having to do with changing our second amendment. We have plenty of rules and regulations. There's plenty of things that they can do right now that are already there,'' said Trump.

"They should be looking at mental health. I mean, we should build, like, institutions for people that are sickos. We have sickos all over the place."

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