someone has to blame it on the US.

"We never thought Palestinian bullets would be directed at us. Most of the people injured were shot in the head. The aim was to kill -- and it was done to satisfy the U.S."

This crackdown is probably Arrafat's attempt at damage control following those reports of people celebrating in the streets after the attacks. I'm sure he's smart enough to realize just how much ill will was generated by those pictures and how much it set back support for his cause. On the other hand, Arrafat also realizes that he isn't fully in control of the situation and could be the next target of the radicals.