The US insists that Iran is providing sanctuary for al Qaeda members who fled from Afghanistan and elsewhere. The government denies this, but the government has no control, and often no knowledge of, the terrorist training and housing facilities run by the Iranian Islamic radicals who control the police, military and courts and have veto power over anything parliament does. So al Qaeda can do whatever it wants in Iran and no one inside Iran can interfere. This is why many Iranians fear that the US will attack Iran, or at least the al Qaeda camps. Many young Iranians joke about wanting this invasion as soon as possible. And the Iranian Islamic radicals fear their less radical countrymen aren't joking.