There are claims that terrorists linked to the al-Qaeda network are planning an attack on a US nuclear power plant to coincide with Independence Day celebrations.
US intelligence sources have told the Washington Postthey are taking the threat seriously.
The new threat reportedly entails an unidentified group targeting Pennsylvania's Three Mile Island nuclear facility or another plant in the north east on July 4th.
News of the plan follows earlier intelligence obtained from Mr Abu Zubaydah (31) who was captured on March 28th. Mr Zubaydah is considered a key lieutenant of bin Laden and an organiser of terrorist-training camps inside Afghanistan.
The detained al-Qaeda chief revealed two of his terrorists are operating in a secret cell in the United States and are planning an attack.
He said a US and an African national were planning to construct a radiological bomb - a conventional bomb fortified with radioactive material - for the attack, the officials said.
"He seems to be supplying some good information to enhance his credibility," said one official. "On the other hand, it could be part of a larger deception effort".