AFTER TROOPS, TERROR.

Reports that U.S. intelligence has been picking up indications that Muslim extremists from Islamic Jihad, Hizballah and other terrorist organizations are entering Iran from Iraq, Syria and Jordan. Concern that once Saddam Hussein is ousted, radicals who may owe their allegiance to neighboring regimes may have their own agenda; Fear that the radicals could incite more suicide bombings aimed at U.S. troops; Speculation that the infiltration could aid U.S. efforts to track down terrorists.