A man who called himself an American promotes holy war in Somalia in a video posted this week on an Islamic militant Web site. A US government contractor who tracks extremist propaganda said that the footage was the first to show what may be an American with a senior role in al-Shabab, a Somali group the State Department considers a terrorist organization with links to al-Qaida. The half-hour video featured an amateur English-language rap soundtrack and purports to show an operation against Ethiopian troops in Somalia. It appeared on Web sites where al-Qaida and other militant groups often post messages and videos. A caption said that it was filmed on July 15, 2008. A tall man with long dark hair and a wide smile who appeared to be in his 20s and gives his nom de guerre as "Abu Mansour al-Amriki," or "the American," urged Muslims around the world to send their children to replace his group's fallen fighters.