In Afghanistan, he says, he was held for five months and tortured, before being released without charge after it was discovered that he had been confused with an al-Qaeda suspect of the same name.

ECONOMIST: Extraordinary renditions

"Security authorities suspect that three of al Qaeda's most dangerous operatives -- Ammar Ubadah al-Waeli, Ayeth Jaber al-Shebwani, Saleh al-Tayes -- may have been also eliminated, " the embassy said.

CNN: Yemen says 6 al Qaeda leaders killed

American authorities appear to have raised their threat level as a wartime precaution, rather than in response to a specific threat, though the Federal Bureau of Investigation gave warning last week that a particularly dangerous al-Qaeda suspect is on the loose and may try to slip into the country.

ECONOMIST: Tense times at home

Pakistani security men say it is ridiculous to suspect any complicity: they are at war with al-Qaeda, have arrested 40 of its leaders, and suffered violent attacks, including on ISI offices and the army's headquarters in Rawalpindi.

ECONOMIST: Pakistan after bin Laden

"I am not aware of any evidence so far that the Boston suspect is part of any organized group, let alone al Qaeda, the Taliban, or one of their affiliates -- the only organizations whose members are subject to detention under the Authorization for Use of Military Force, as it has been consistently interpreted by all three branches of our government, " he said.

CNN: SHARE THIS