6:15 p.m.:
FBI Director Robert Mueller (right) said the identity of most of the hijackers is now known. "We have, in the last 24 hours, taken the (passenger) manifests and used them in an evidentiary base. And have successfully, I believe, identified many of the hijackers on each of the four flights that went down." In other news, firefighters and police said they were warned of One Liberty Plaza's imminent collapse and ordered everyone out of the area. There were no immediate reports of injuries.