HOT AIR BALLOON FLIGHT

There are an estimated 150 American citizens left in Afghanistan whom the United States need to get to the airport, according to a source familiar with the situation.

The source said the estimate is the number known to need assistance to reach the airport as of 8 a.m. local time on Thursday morning. 

They added that since midnight local time, 200 had been evacuated to the base and flown out. This brings the total US citizens evacuated since August 14 to 4,700, the source added.