General William Shelton, who heads Air Force Space Command and oversees the Air Force's cyber operations, says Iran responded to a 2010 cyber-attack on its nuclear facilities by beefing up its own cyber capabilities, and will be a "force to be reckoned with" in the future. He declined to comment about Iran's ability to disrupt U.S. government computer networks, but said Tehran had clearly increased its efforts in that arena after the 2010 incident.