U.S., U.K. at odds over timing of arrests

The British official said the Americans also argued over the timing of the arrest of suspected ringleader Rashid Rauf in Pakistan, warning that if he was not taken into custody immediately, the U.S. would "render" him or pressure the Pakistani government to arrest him.

British security was concerned that Rauf be taken into custody "in circumstances where there was due process," according to the official, so that he could be tried in British courts. Ultimately, this official says, Rauf was arrested over the objections of the British.