Gen. David Petraeus officially took his post as director of the Central Intelligence Agency Tuesday morning. Vice President Joe Biden led a private swearing-in ceremony at the White House.

“You led the 9/11 generation, turned it into the greatest group of warriors this country has ever seen,” Biden said, according to a pool report. 

Petraeus is the most high-profile general of his generation, and he led the U.S. counterinsurgency missions in the Middle East in recent years. The four-star general retired from the U.S. Army last week.

In the swearing-in ceremony, Petraeus joked about the interim between his Army service and his new job as the CIA’s 20th director. 

“It’s been a terrific week,” he said.