The Pentagon is sending Fleet Anti-Terrorism Teams, known as FAST teams, a U.S. defense official has confirmed to the E-Ring.
The official was unsure if the teams were actually en route to Libya yet.
"Make no mistake, justice will be done," President Obama said, in a statement in the Rose Garden early Wednesday. Defense Secretary Leon Panetta is not expected to appear on camera today.
UPDATE: A U.S. defense official confirms to the E-Ring there are "about 50" people in the FAST teams deployed to Libya. Pentagon officials won't say with specificity yet if the teams will protect just the U.S. embassy in Tripoli or additional sites, including the consulate in Benghazi.
"The goal is to shore up security around our installations," said a US defense official, and work to get the Libyans back in control of security.
Libyan officials, the US official said, are "being very cooperative" with the Pentagon and "doing all of the right things," but "obviously there was some breakdown" of security.
Still unknown is how long the teams could stay. A senior military official told the E-Ring that FAST teams could stay "as long as needed -- days, weeks, even months." Their deployment could be a precursor to additional troop deployments, the official said, but doesn't have to be.
UPDATE: The U.S. Marine Corps' FAST Team members are on the ground in Libya, at the U.S. embassy in Tripoli, a senior administration official confirmed. They came from Naval Station Rota, in Spain.