MacDILL AIR FORCE BASE, Fla. — The morning sun had barely cast its fresh light over Tampa Bay when Ardashir Safavi — born in Iran, a refugee to Turkey, educated in the mid-Atlantic states — was up and patrolling two dozen Persian-language Web sites, hunting militant adversaries in cyberspace.

His mission was to scan news reports, blogs, social media and online essays to identify those he viewed as “containing lies, misinformation or just misperceptions” about American military operations and Pentagon policy across the Middle East.

In recent months, Mr. Safavi and his teammates spotted posts that included doctored photographs of Osama bin Laden purporting to prove that Al Qaeda’s leader had not died in an American commando raid. They turned up blogs stating that the Pentagon was accelerating war plans for invading many Muslim nations, and others amplifying Taliban accusations that American troops rape with impunity across Afghanistan.

Mr. Safavi works as part of the Digital Engagement Team, established in 2008 by the military’s Central Command to “counter extremist ideology, promote cultural awareness and explain U.S. interests,” said Maj. David E. Nevers, the team’s chief officer, who must approve all responses before they are posted on foreign-language Web sites.