andrea mitchell has more on this. >> good morning, yasmin. the group claiming responsibility is an offshoot of the barbaric organization that originally formed in iraq and syria but this isis branch started in pakistan and now a bitter rival of the taliban in afghanistan, while vowing to continue targeting u.s. forces. with just four days until president biden's deadline of with drawing from afghanistan a growing threat to the evacuation of the remaining americans and afghan allies. the terror group known as isis-k. >> i repeatedly said this mission was extraordinarily dangerous and why i've been so determined to limit the duration of this mission. >> what is isis-k? an offshoot in afghanistan of the islamic state, the group formed six years ago in pakistan has now taken root in afghanistan, gaining even more force with the taliban during