<p>Osama bin Laden's al Qaeda network has become deeply involved in international drug trafficking, using the money to buy arms and, possibly, radioactive material for use in a so-called "dirty" nuclear bomb, senior U.S. officials say.</p>
<p>The seizure earlier this month of boats carrying heroin and hashish, and operated by al Qaeda-linked persons, has brought to light an al Qaeda drug operation that has grown tremendously since the September 11 attacks, the sources say.</p>