Republican presidential front-runner Donald Trump on Monday called for a ban on Muslims entering the United States in the most dramatic response by a candidate yet to last week's shooting spree by two Muslims who the FBI said had been radicalized.


"We have no choice," Trump said at a rally in South Carolina, warning of more September 11-style attacks if stern measures are not taken.


Trump's statement on "preventing Muslim immigration" drew swift and fierce blowback from many directions, including the White House, rivals for the 2016 Republican presidential nomination, Democratic presidential front-runner Hillary Clinton and Republican former Vice President Dick Cheney, who said the idea "goes against everything we stand for and believe in."


"Donald Trump is unhinged. His 'policy' proposals are not serious," Republican presidential hopeful Jeb Bush said in a tweet.


Other social media reaction led hashtags such as #racism, #fascism and #bigot to trend heavily. Withering reaction also came from Ohio governor John Kasich, Senator Lindsey Graham of South Carolina, New Jersey Governor Chris Christie and Senator Marco Rubio of Florida.