The message refers to the revolutions in Egypt and Tunisia but doesn't mention the uprisings in Libya, Yemen, Syria or elsewhere.
The official spoke on the condition of anonymity due to the classified nature of the information.
The official said it is "puzzling" that bin Laden would "suddenly join the bandwagon on the uprisings," months after they started and not mention all of the Arab nations in turmoil. For instance, the official said it was a "head scratcher" why bin Laden would not indicate his support for the uprising against Libyan leader Moammar Gadhafi, a man bin Laden detested.
"Why not try to inspire AQIM," said the official, referring to al Qaeda in the Islamic Maghreb, a regional affiliate.
Since protests began across the Middle East, U.S. officials have said the movement undermined al Qaeda and offered an alternative to dissatisfied youth.
"The revolutions in Tunisia and in Egypt and the protests elsewhere that are leading to reforms in a number of governments I think are an extraordinary setback for al Qaeda," Secretary of Defense Robert Gates said on March 1. "It basically gives the lie to al Qaeda's claim that the only way to get rid of authoritarian governments is through extremist violence."
The U.S. official also said that among the seized materials were written communications from bin Laden expressing his desire to see U.S. President Barack Obama assassinated.
The United States expects to have further interrogations of the three wives of bin Laden who were taken into custody by Pakistani authorities after the U.S. raid on the compound. The U.S. official concurred with a description of the meeting on Friday with all three wives as hostile.