Secret Service Director Joseph Clancy says some video footage of a March 4 incident at the White House involving two senior agents has been recorded over.

Clancy says the agency is working with the security system's manufacturer and Homeland Security Department officials to try to recover the lost footage.

The missing video likely includes images of a pair of senior agents accused of pushing a construction barrel with their vehicle as they drove through a secure area while other, on-duty agents and officers investigated a suspicious item. The DHS inspector general is investigating the incident, including allegations that the agents had been drinking before driving into the White House complex.

Clancy says it is standard practice to record over security videos after 72 hours.