Chaotic scenes unfolded after two terrorist attacks occurred outside Kabul airport.
The threat level had been high for days, and the shear volume of people, the lack of bag checks, and the numbers of unprotected soldiers were an indicator that the area was an easy target.
The casualties are high, and civilians would not have noticed anyone acting strangely beforehand amid evacuations.
Some international soldiers had already withdrawn because of the threat, but the US and British forces did not have that luxury.
It is believed the suicide bomber waited until a number of soldiers approached to help a family out of the canal near the airport.
The Taliban had been cooperating with the international forces for days, and they have condemned the attack.