GOP frontrunner Donald Trump said that President Obama apologized to Muslims when he visited a mosque earlier this week.

“And then President Obama yesterday goes to a mosque and he apologizes,” Trump said as the crowd booed in response. “I mean, what’s going on?”

Trump previously criticized Obama’s visit to a mosque in Baltimore, saying, “Maybe he feels comfortable there.”

Trump told the audience at his campaign rally in Florence, South Carolina on Friday night that Christianity is under siege. He urged that churches should unite on political issues, but they don’t because they are “afraid to lose their tax-exempt status,” the real estate mogul explained.

“You have the most beautiful churches I’ve seen,” Trump said of the churches in South Carolina. “I almost wanted to just go in and pray.”