Two American citizens were killed in two separate accidents blamed on Jordan's freak blizzard last week, Jordanian officials said Sunday. In the first reported accident, a 76-year-old tourist suffered a fractured skull after slipping off a bridge in Jordan's famous historical site Petra on Saturday, said Col. Farid al-Sharaa, a Civil Defense Department spokesman. He said the tourist was rushed to a nearby hospital, but died after receiving first aid treatment. Prior to the man's death, tourists had been advised to stay away from Petra, the ancient rose-red rock city recently named one of the new seven wonders of the world, because heavy snowfalls had created slippery conditions.