Osama bin Laden's captured aide is thought to have been plotting a new wave of terror attacks on the US before he was seized.
Washington officials have studied documents found in a raid on Mr Abu Zubaydah's safe house in Pakistan.
They say the material suggests he was in the later stages of organising strikes on US interests.
The documents, including computer discs, videotapes and financial records were found in the raids in Faisalabad.
Mr Zubaydah is believed to have become bin Laden's chief of military operations following the death of Mr Mohammed Atef, who was killed in US bombing raids in Afghanistan in November.
He had set up a new command centre in the safe houses to reorganise al-Qaida and help it hit back at the US, the New York Post reported.
The 30-year-old was believed to involved in activating terror cells already in place around the globe.
Mr Zubaydah is expected to be one of the first al-Qaida suspects to face the military tribunals being organised by the US government.
The Palestinian is accused of playing a key role in the September 11th terror atrocities, the attack on the USS Cole in Yemen and the aborted millennium plot against Los Angeles Airport.
He is expected to be taken to the Camp X-Ray US naval base in Cuba where other al Qaida and Taliban suspects are being held.
PA