Time and again, Rev. Franklin Graham has stressed the need for American leaders to be more careful in letting immigrants into the country. The recent sexual attacks by Muslim migrants in Germany on local women have only made Graham more convinced that immigration control must be heightened further.

"Gangs of Muslim men from North Africa and the Middle East roamed the streets of Cologne, Germany, on New Year's Eve attacking over 100 women — beating, groping, and raping," he wrote on his Facebook page. "Unbelievably, authorities tried to cover it up because of fear and political correctness. Reports say that police were blocked from helping the women by groups of migrant men and were pelted by glass bottles and fireworks. This is a nightmare."

Graham said the attacks might have something to do with the fact that Germany took in a whopping 1.1 million asylum seekers last year.

"And look what is happening," he warned. "If we don't properly vet people that we allow to come into this country, this could happen here. I hope the Washington politicians — Republicans, Democrats, and the White House — see and recognise this very grave danger."

In a subsequent Facebook post, Graham conceded that "the enemy" has already penetrated the United States. "My fellow Americans, the enemy is here," he said, as he cited the news story of a 30-year-old gunman who tried to kill a Philadelphia police officer in the name of Islam.

"We have cause to be alarmed at these stories and at the number of potential terrorists and jihadists we having living inside our borders right here on American soil. It's not a secret — their goal is to kill all those who do not follow Islam and expand the territory of the Islamic State to the entire world," he said.