Marked by the U.S. Embassy seal, advertisements condemning an anti-Islam video appeared on Pakistani television on Thursday in an apparent attempt to undercut anger against the United States, where the film was produced. Hundreds of youths, however, clashed with security officials as they tried in vain to reach the embassy in Islamabad amid anger in many countries over the film's vulgar depiction of the Prophet Muhammad. The advertisements appear to be an effort by the U.S. government to dampen chaos surrounding the film and undo some of the damage to America's image in the Muslim world. Violence linked to the...