U.S. Defense officials are keeping a watchful eye on possible terrorist attacks as the 10th anniversary of 9/11 terror attacks approaches, Pentagon Spokesman Dave Lapan said Friday.

Lapan said the department "will obviously be ... watching closely (and maintaining) increased vigilance. We may take additional security steps based on information," as there is always a risk of aspirational terrorist attacks against the United States from al-Qaeda and other groups.

"After the raid on the bin Laden compound, we turned up information that suggested that attacks around the anniversary of 9/11 is something they were pursuing," Lapan said, noting that information was very general and no specific attack plans have come to light.

Lapan said the Pentagon's threat assessment is in line with that of Secretary of Department of Homeland Security Janet Napolitano, who said in a press release earlier in the day that " there is no specific or credible intelligence that al-Qaeda or its affiliates are plotting attacks in the United States to coincide with the 10-year anniversary of 9/11."