Sources told ABC that intelligence analysts believe bin Laden's followers may consider him irrelevant if he is not heard from at such a critical time.

A taped message from bin Laden was released a few days before the 2004 presidential election. Exit polls showed that voters who thought the tape was important were more likely to have chosen the Democratic nominee, Sen. John Kerry of Massachusetts, over President Bush.

Analysts also fear that al-Qaida might launch an attack against the United States around the election. This is not based on any specific intelligence but has led to the declaration of a "period of heightened alert."

Officials told ABC that bin Laden may have trouble releasing a message because of intensive efforts to keep al-Qaida and other terrorist groups from using the Internet to spread propaganda.