Attorney General John Ashcroft urged Southeast Asian nations Wednesday to cooperate with one another and the United States in the fight against terror. But he said the United States could not accede to a request by Indonesia’s president, Megawati Sukarnoputri, for immediate access to a top operative of one of the country’s major terrorist groups, Jemaah Islamiyah. The operative, Riduan Isamuddin, better known as Hambali, is in American custody and is wanted here for interrogation. American officials describe Mr. Isamuddin as the organizer of the bombing of two nightclubs on the Indonesian island of Bali that killed 202 people in October 2002. Most of the victims were young tourists from Australia. Mr. Isamuddin, a member of Osama bin Laden’s inner circle, was captured by the Central Intelligence Agency in Thailand last August. Full Story