“All engagements are transparent and attributable.”

NYTimes | 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.

The team includes 20 native speakers of Arabic, Dari, Persian, Pashto, Urdu and Russian, the latter a shared language across the Muslim countries of the former Soviet states of Central Asia. Given that Central Command is responsible for military actions in an arc of instability stretching from the Indian Ocean across the Persian Gulf to the Red Sea, people here call their headquarters “Tampa-stan.”

The government’s expanding efforts in computer-network warfare, offense and defense are among the most secret enterprises carried out by the military and intelligence community. To counter the adversary’s use of the Internet, American cyberwarriors have hacked into extremist chat rooms to sow confusion, or to inject poisonous code to take down militant Web sites. Sometimes, they choose not to act, but silently track the online movements of jihadists to learn their plans.

In contrast, the Digital Engagement Team operates in total sunshine: all of the online postings carry an official stamp acknowledging sponsorship by Central Command.

The team’s operators “respectfully deflect baseless and often irrational insults, confront adversaries with factual evidence and expose extremist propaganda that might otherwise go unrefuted,” Major Nevers said. “All engagements are transparent and attributable.”

The only obfuscation is the use of online pseudonyms to protect the civilian contract employees from potential retaliation.