WASHINGTON, April 23: A top aide to Osama bin Laden has said the Al Qaeda network is attempting to build a “dirty bomb”, CBS television said on Monday, but the network added it was unclear if the claim was true.

CBS said government sources told it that Abu Zubaydah, who was Osama’s chief of operations until his capture, revealed the information to interrogators.

“Abu Zubaydah has told interrogators Al Qaeda is attempting to build a so-called dirty or radiological bomb that would be used against the United States to spew radiation into the atmosphere,” the network said.

Zubaydah also told interrogators Al Qaeda knew how the weapon could be smuggled into the United States.

The network added that officials were unsure whether Zubaydah was “telling the truth or bragging”.

It said an FBI public warning issued on Friday to banks in the United States was based on a claim by Zubaydah that Al Qaeda was planning attacks on financial institutions.

It said no warning had been issued about the bomb “apparently because Zubaydah did not say Al Qaeda actually has one” and officials “don’t know whether Zubaydah is telling the truth or bragging — or both”.

Considered the chief recruiter for Al Qaeda, Zubaydah was being held in an undisclosed location and had been treated for three gunshot wounds received during his capture in Pakistan last month.—Reuters