Glenn Beck says a privately sponsored rescue mission has successfully evacuated 5,100 Christians and other vulnerable people from Afghanistan.

A fundraising campaign led by the Blaze presenter raised over $30m towards the airlift, which was carried out on the ground by the Nazarene Fund, a US non-profit that works to support persecuted Christians.

The evacuation mission was aimed at Christians but other at-risk people, including women and US nationals, were also airlifted on the flights.

The evacuation flights have ended after the US started withdrawing troops from Kabul following a deadly terrorist attack on Thursday that killed at least 170 people, including 13 US Marines.

Beck said, "We will not forget those left behind. Our mission there gets tougher and more dangerous."

He said the refugees are now in an undisclosed country awaiting settlement. 

"We also still have more work to do as now we have 5,100 refugees sitting in another country wondering who will claim them? Sadly, but certainly not America," said Beck. 

He added, "May God bless the refugees and new home countries and may He heal their land. These refugees are good and faithful servants that make me embarrassed to call myself Christian." 

Tim Ballard, CEO of the Nazarene Fund, said he was concerned about those left behind. 

"This also includes Christians," he said in a Facebook update. 

"Now while these Christians aren't American citizens ... consider the fact that if you're a girl who's 19-years-old, all you've known is freedom based on the protection the United States government offered.

"I mean, we've been there for 20 years, it's all they've known - the freedom to be able to say I'm a Christian or I'm whatever, I can convert to any religion.

"And we promised that to them and now we're leaving them."