Republican presidential frontrunner Donald Trump is pledging to "go strongly" against those making the "great assault on Christianity" both in the US and in the Middle East should he be elected US president in November next year.

In a radio interview on Yelowhammer Radio with Cliff Sims on Friday last week, Trump also noted that part of the attack on Christianity in the US is what he called the "war on Christmas."

"There's an assault on anything having to do with Christianity," Trump said. "They don't want to use the word Christmas anymore at department stores."

"There's always lawsuits and unfortunately a lot of those lawsuits are won by the other side," he said. "I will assault that. I will go so strongly against so many of the things, when they take away the word Christmas."

Trump said he's one of the people who go out of their way to use the word "Christmas," even though he had been explicitly told not to on several occasions.

He said Christianity is also under attack in the Middle East. "There's real assault on Christianity when you look at what's going on in Syria and ISIS," he said. "Do you know that if you're a Christian from Syria, you cannot get into the United States? If you're a Muslim from Syria, it's one of the easiest places to get into the United States from?"

When asked to describe his faith, Trump proudly answered that he is "somebody that believes very strongly in the Bible, believes in God."

"I'm Protestant," he said. "I'm Presbyterian to be exact. And I grew up in Sunday school, and I did all of the things that you probably did. And I believe very, very strongly. I'm a big believer in the Bible."

Trump admitted that he rarely asks forgiveness from God, since every time he makes a mistake, he becomes too busy trying to fix it and make amends. "I just go on and try to do a better job from there... I think if I do something wrong, I think, I just try and make it right. I don't bring God into that picture. I don't," he said.

During a separate event in Alabama over the weekend, Trump compared himself to one of the greatest American evangelists of all time—Billy Graham. Graham's last rally drew 242,000 people. Trump drew 30,000 Alabamians during last week's campaign sortie.

Despite the contrasting numbers, Trump said he was still happy with the turnout, adding, "Now I know how the great Billy Graham felt."