retaliatory attack on isis-k and what kind of time frame that might or should happen in? >> it should come as swiftly as possible. i believe general mckenzie said they're searching hard for isis-k and the perpetrators of this attack. kabul is a city of 4.5 million people. it's a huge place. it's going to be very difficult for us to find isis-k. another point that needs to be made since general mckenzie described how closely they had been working with the taliban. as you mentioned earlier, the part of the taliban in charge of security in kabul now is the hakani network. very famously they've been one of the brutal terrorist networks operating in afghanistan the last 20 years. they're perhaps the most organized terror group in the world right now. they are in charge of security