US counterterrorism agencies have not detected a significant al-Qaida operational capability in the United States since the 2003 arrest of an Ohio truck driver who was in the early stages of plotting to destroy New York City's Brooklyn Bridge. Nevertheless, al-Qaida's capabilities aren't clear and the group remains a viable and dangerous threat, the new deputy director of the National Counterterrorism Center, Kevin Brock, told The Associated Press. The uncertainty shows the tension increasingly facing national security officials as they pursue terrorists, even as the country has gone four years without a domestic attack from Osama bin Laden's terror network. Brock was the FBI's special agent in charge of the Cincinnati office that investigated Iyman Faris, who is serving a 20-year prison sentence for aiding and abetting terrorism and conspiracy. Faris, a Pakistani by birth who became a US citizen in 1999, was trying to determine whether he could ruin the Brooklyn Bridge by cutting the suspension cables. Brock said the case showed him al-Qaida's weakened state after the attacks of Sept. 11, 2001. Faris didn't strike Brock as someone who could carry out a sophisticated plot, even though he had been chosen by a top al-Qaida leader now in custody, Khalid Shaikh Mohammed, to handle complicated operations.