"I think it's unprecedented that a large file such as this is going to be distributed en masse, " said Jonathan Heiliger, chief executive officer of Frontier GlobalCenter, which runs the Yahoo search engine.

CNN: Record traffic reported; government sites swamped

Police officer Amjad Khan told the Associated Press the blast hit a platoon of 43 Frontier Constabulary troops in a truck near the police district headquarters.

CNN: Suicide blast kills 24 in Pakistan