Police are investigating possible arson to two buses belonging to a company that began offering special bus lines to transport West Bank Palestinian passengers.
Following a confrontation at a West Bank military base, Prime Minister Benjamin Netanyahu ordered Israeli security forces to "act aggressively" against Jewish activists who attack soldiers.
Kalkilya is surrounded on all sides by what Israel calls the separation fence, a barrier the government says it must build to protect its citizens from suicide bombers, snipers and other Palestinian terrorists.
Residents of Kalkilya say it has turned their city into a ghetto.
But Kfar Saba residents are solidly behind the wall.