There was no immediate claim of responsibility, but U.S. officials said the tightly coordinated operation bears the hallmarks of Osama bin Laden, the Saudi-born dissident now living in Afghanistan who is blamed for bombing two U.S. embassies in East Africa and other anti-American attacks. There is no evidence that’s been presented at this point to prove their assertions. A Pakistani newspaper, Khabrain, said bin Laden had denied blame. “The terrorist act,” it said, “is the action of some American group. I have nothing to do with it,” it quoted him as saying via sources close to the Taliban. The Taliban movement, which rules most of Afghanistan, said bin Laden could not have been involved. Western aid workers in Kabul began pulling out of the Afghan capital amid fears for their safety if the United States retaliates. A special U.N. flight carried some aid workers out of Kabul in the middle of the day, and United Nations said it’s considering a general withdrawal of its foreign staff from the battered country.