"These are people that are outside the country, so we're really not talking about the Constitution," the GOP presidential candidate said during an interview on ABC's "Life with Kelly and Michael."
"And it's not about religion. This is about safety," Trump said. "This has nothing to do with religion. It's about safety."
Trump's proposal has roiled the U.S. political debate since it was released Monday and has been condemned across the domestic political spectrum and by foreign leaders. GOP rivals have blasted Trump as "unhinged" and his proposal on Muslims as "un-American" and "unconstitutional," though he has stood by the idea.
Trump pushed back again Wednesday when co-host Michael Strahan asked Trump whether he released the proposal just to be "outrageous."
"No, no, not to be outrageous. Look, we have a problem in this country," Trump responded, mentioning 9/11 and last week's mass shooting in San Bernardino, Calif.
"Frankly, a lot of people knew that was going to happen," Trump claimed. "A lot of people knew he had those guns and the rifles and the bombs, bombs all over the apartment."
"You look at what went on in Paris. We have tremendous problems, it's getting worse and worse and those problems are coming from a certain sector," Trump said. 
"Our country has to get its act together," Trump said. "We need safety."