"My guess would be that we probably will (add more people to the terrorist watch list," Holder told lawmakers at a Congressional hearing.
"The material that was seized from that residence is being reviewed by an interagency team. CIA, Justice, other intelligence agencies, other law enforcement agencies are all contributing people and machines to go through that material," he said.
The material recovered include 10 hard drives, five computers and more than 100 storage devices, such as disks, DVDs and thumb drives.
"As we glean information from that material, we will make appropriate decisions with regard to who might be added to the terrorist watch list, the no-fly list, all those things," Holder said.
The commandos also recovered five cell phones, audio and video equipment, "lots" of paper documents and some five guns.
"I think that we will ultimately be safer as a result of his death, but in the short term I think we have some serious concerns that we have to be ready to address," Holder said, adding that killing of bin Laden by the US forces in Pakistan was lawful.
"Let me make something very clear. The operation in which Osama bin Laden was killed was lawful. He was the head of al-Qaeda, an organization that had conducted the attacks of September the 11th. He admitted his involvement. As you indicate, he said he would not be taken alive. The operation against bin Laden was justified as an act of national self-defense. It's lawful to target an enemy commander in the field," he argued.
"So he was, by the estimation of the Justice Department, a lawful military target and the operation was conducted in a way that's consistent with our law, with our values. If he had attempted to surrender, I think we should obviously have accepted that, but there was no indication that he wanted to do that, and therefore his killing was appropriate," Holder said.
The Attorney General said the decade-long manhunt for bin Laden came to a successful end this week.
"This historic achievement was a tremendous step forward in attaining justice for the nearly 3,000 innocent Americans who were murdered on September the 11th, 2001," he said.
"I hope it will inspire a renewed commitment to collaboration across party lines, branches of responsibility and agencies, so that we can effectively address the most pressing challenges facing the American people," Holder said.