CAIRO - Days of planning and online promotion by hard-line Islamist leaders helped whip up the mobs that stormed the U.S. Embassy in Egypt and launched a deadly attack on the U.S. Embassy in Libya that killed an ambassador and three others.
As the U.S. tightened security worldwide at embassies and Libya's president apologized for the attack, details emerged of how the violence began, according to experts who monitor Egyptian media.
