Washington - There is a higher risk of a terrorist attack in the United States during the transition between the Bush and Obama administrations, the nation's top homeland security chief said Wednesday.

"Any time there's a transition there's a danger or a risk that vulnerability (to terror attacks) will increase because people become distracted," Homeland Secretary Michael Chertoff said, according to CNN. "People are leaving; people are coming in and that's a disruptive process for any organization."

President George W Bush pledged Wednesday to ensure a smooth transition with President-elect Barack Obama's team to ensure there are no disruptions to security and foreign operations. (dpa)