The Bush administration urged UN investigators Tuesday to look into an allegation by a former Syrian vice president that President Bashar Assad had threatened former Lebanese Prime Minister Rafik Hariri several months before Hariri was assassinated. The allegation was made last week by former Vice President Abdul-Halim Khaddam, who left Syria several months ago. Khaddam said Assad warned Hariri months before his assassination last year that he would "crush whoever attempts to overturn our decision" to extend the term of Lebanon's pro-Syrian president. Referring to Khaddam's allegation, State Department spokesman Sean McCormack said, "I think his remarks warrant further investigation" by the United Nations. Mehlis already has implicated senior Syrian officials in Hariri's assassination. Syria has dismissed the charges as unfounded.