The unrest engulfing Arab streets and threatening authoritarian governments in the Mideast is complicating U.S. counterterrorism efforts, scrambling the volatile battleground against al-Qaida in Yemen and raising concerns about the durability of Egypt's stance against militants.

U.S. counterterrorism officials need to move quickly to firm up relationships with veteran Mideast intelligence and security services in the aftermath of momentous changes, experts say. Lingering confusion over who will take the reins of power could hamper instant decision-making in the short term.