The Houston Chronicle June 23, 2001, Saturday 3 STAR EDITION SECTION: A; Pg. 1 LENGTH: 750 words HEADLINE: U.S. forces put on alert in Mideast; Terrorist threat perceived SOURCE: Staff BYLINE: MICHAEL HEDGES, Houston Chronicle Washington Bureau DATELINE: WASHINGTON BODY:WASHINGTON - A Marine Corps mission in Jordan was abruptly halted Friday and Navy ships were hustled out of a Persian Gulf port in Bahrain after a threat against Americans was received, military officials said. At the same time, the State Department was preparing to update a worldwide caution to Americans of security concerns abroad, a spokesman said. The threat was...