>> reporter: the protesters in yemen set out to destroy the american embassy in sanaa to punish an insult against islam. protesters climbed the perimeter fence, undeterred by yemeni security forces who tried to keep them back with water cannons. the crowds pushed forward and managed to get inside the embassy parking lot, smashing windows, torching vehicles, using a fork lift to do even more damage. this time, the u.s. embassy was prepared. staff was moved to a safe location. no one was hurt. in cairo, another embassy under siege, but egyptian security forces are finally taking decisive action. riot police battled demonstrators all day. more than 200 were overcome by tear gas. as the air burned with the stuff, protesters told me their goal was to get to the cairo embassy and take vengeance.