Donald Trump says that had he been president, the Sept. 11 hijackers likely would not have gotten into the U.S. in the first place.

The billionaire developer is leading most polls for the GOP presidential nomination and says on "Fox News Sunday" that if he were "running things...there's a good chance that those people would not have been in our country."

All but one of the 19 men who hijacked planes and flew them into the World Trade Center, the Pentagon and a field in Pennsylvania legally entered the country on business or tourist visas. One entered on a student visa but did not show up to class.