An al-Shabaab recruitment video has prompted Donald Trump to defend his call to ban all Muslims from entering the US.

In an interview with CBS News aired yesterday, Trump – who is currently the Republican presidential candidate frontrunner – said, "Look, there's a problem. I bring it up."

"Other people have called me and say, 'You have the guts bring it up because frankly, it's true but nobody wants to get involved,'" he continued. "Now people are getting involved.

"People that are on different persuasions than me right now... are saying, you know maybe Trump isn't wrong. We want to examine it."

Trump spoke after featuring in a recruitment video by Somali terrorist group al-Shabaab.

The video used a clip of Trump urging the US to ban Muslims from entering the country to suggest that America discriminates against its Islamic population.

Trump's anti-Muslim rhetoric has prompted significant criticism, including from a number of his fellow candidates. Jeb Bush has branded Trump "unhinged" while Lindsey Graham – who in Demcember withdrew from the presidential race – has accused him of being "downright dangerous".

Democratic presidential candidate Hillary Clinton last month accused Trump of being ISIS' "best recruiter"

The US needs to ensure "the really discriminatory messages that Trump is sending around the world don't fall on receptive ears," she said during a Democratic debate.

"He is becoming ISIS's best recruiter. They are going out people showing videos of Donald Trump insulting Islam and Muslims in order to recruit more radical jihadists."

CBS' John Dickerson asked Trump on Sunday whether he was concerned about being used as a recruitment tool by al-Shabaab.

"They use other people, too," Trump said.

"What am I going to do? I have to say what I have to say. And you [know] what I have to say? There's a problem. We have to find out what is a problem. And we have to solve that problem."