CARSON THIRD IN POLL

Carson had been rising in polls, although he gave up some ground in a CNN/ORC poll released on Sunday, slipping to third place from second with 14 percent support. Sixteen Republicans are seeking the party's nomination for the presidential election in November 2016.

The CNN/ORC poll showed Trump, a real estate mogul, continued to lead the contest with the support of 24 percent of registered voters, down from 32 percent in a previous poll. (http://bit.ly/1OnmXrB)

Former Hewlett-Packard Chief Executive Officer Carly Fiorina surged into second place with 15 percent support.

Carson's comments drew scorn from Republican Senator Lindsey Graham, another presidential candidate.

"I think Dr. Carson needs to apologize," Graham said, adding the comments were particularly offensive to US soldiers who are Muslim.

A Des Moines Register/Bloomberg poll conducted in January in Iowa, the first state to vote in the nominating contest, showed 39 percent of Republicans saw Islam as inherently violent, compared with 13 percent of Democrats.

Trump, asked on "Meet the Press" if he would accept a Muslim president, replied: "Some people have said it already happened."