In the months following Operation Medusa, Afghan and international concern over the number of civilians killed in the assault intensified. In particular, in October a NATO investigation into an airstrike found that 31 civilians were killed, including twenty people from a single extended family. On 3 January 2007, a NATO spokesman acknowledged that "The single thing that we have done wrong — and we are striving hard to improve on next year — is killing innocent civilians." The follow-up operation, Operation Falcon Summit, generally did not involve such heavy firepower, instead using small infantry units searching villages in co-operation with tribal elders.