Afghanistan's Christians are already paying the price for their faith as the last remaining British and US troops prepare to leave, according to one religious freedom expert. 

"I'm not exaggerating by saying that the Taliban are killing Christians," said Nina Shea, director of the Hudson Institute's Center for Religious Freedom. 

She told Blaze TV that the Washington DC-based think tank was trying to get one Christian man out whose brother and father had been killed in the last week. 

"And he is in hiding near the airport hoping to get out, hoping to be rescued because he will be next. And it's because he's a Christian." 

Shea said it was so dangerous for Christians in Afghanistan now because most were converts from Islam.

"And that is considered in the Taliban's eyes to be apostasy that must be punished with death," she said.

But she added that Afghan Christians are "doubly jeopardized" because they are "conflated with Americans and the West". 

"So when the Taliban sees them, not only are they considered apostate, which is punishable by death, but they are considered the enemy." 

Last week, Dr Rex Rogers, President of Christian media ministry SAT-7 North America, said there were reports of Afghans being killed on the spot if they are identified as Christian.

Another Christian told SAT-7 that their family members were receiving death threats.

Dr Rogers said, "We're hearing from reliable sources that the Taliban demand people's phones, and if they find a downloaded Bible on your device, they will kill you immediately.

"It's incredibly dangerous right now for Afghans to have anything Christian on their phones. The Taliban have spies and informants everywhere."