text: Kin plead for 2 Americans, Briton to be released; 2 clerics slain &lt;b&gt;...&lt;/b&gt; Relatives pleaded Monday for the release of two Americans and a Briton held hostage as a deadline loomed for their beheading. In Baghdad, gunmen assassinated two clerics from a powerful Sunni Muslim group opposed to the US presence in Iraq.