WASHINGTON (AP) — The CIA is under pressure from a Senate committee to declassify parts of a congressional report on harsh interrogations of suspected terrorists, but the agency does not give up its secrets easily.

The CIA officials who decide which secrets can be revealed have wrestled with Congress, archivists, journalists, former CIA employees and even a former CIA director. The CIA has used internal reviews of classified materials and a separate process that scans proposed books about intelligence practices to tightly guard what is known about its activities.

A CIA spokesman said the agency was carrying out an "expeditious classification review" of the Senate Intelligence Committee's 400-page findings on the agency's harsh interrogations. He would not estimate a completion date.