Christians in Afghanistan are reportedly hiding indoors for fear of the Taliban days after they took control. 

It is "too dangerous" for Afghanistan's Christians to venture outside, one leader there said.

Speaking anonymously to anti-persecution ministry International Christian Concern (ICC), they said that although the Taliban has promised an amnesty, there are fears that they will soon start targeting Christians.

"We are telling people to stay in their houses because going out now is too dangerous," the Christian leader said.

But they warned that intimidation tactics have already commenced, with threatening phone calls in which Christians are told, "We are coming for you."

The Christian leader fears that it is only a matter of time before the killing of Christians starts and when this happens, it "will be done mafia style".

"The Taliban will never take responsibility for the killings," they said.

The fears of Christians are not only for themselves but for their children.

"Many Christians fear the Taliban will take their children, both girls and boys, like in Nigeria and Syria," the Christian leader explained.

"The girls will be forced to marry Taliban fighters and the boys will be forced to become soldiers. Both will be sent to madrassas to be brainwashed."

The last week has seen harrowing scenes at Kabul airport as thousands of Afghans make a desperate attempt to flee the country. 

Video footage on Thursday showed a little girl being passed to a soldier, prompting British Defence Secretary Ben Wallace to say that Britain will not be able to evacuate unaccompanied minors. 

"We can't just take a minor on their own," Wallace told Sky News.