The U.S. can expect a terrorist attack using nuclear or biological weapons in the next five years.So says a new report out of Washington...The Commission on the Prevention of WMD Proliferation and Terrorism says the incoming administration should focus on the threat, and recommends that one official on the National Security Council focus exclusively on fighting the spread of nuclear and biological weapons.The report finds terrorist groups still lack the ability to make weapons out of pathogens or nuclear bombs.But it warns that gap can be easily overcome, if terrorists find scientists willing to share or sell their know-how.