WASHINGTON (Reuters) - Despite increasing concern about terrorist threats to the United States, the FBI before the Sept. 11, 2001, attacks was hampered by a culture resistant to change, inadequate resources and legal barriers, the national commission investigating the attacks said on Tuesday. "From the first World Trade Center attack in 1993, FBI and Department of Justice leadership in Washington and New York became increasingly concerned about the terrorist threat from Islamic extremists to U.S. interests both at home and abroad," said the report, presented at a commission hearing. Attorney General John Ashcroft, his predecessor, Janet Reno, former FBI Director...