Two Palestinians infiltrated a Jewish settlement in the West Bank and attacked students at a religious school before being shot dead, police say.
Witnesses said the two men, who were disguised as Israeli soldiers, managed to stab two students in Kfar Etzion, near Bethlehem, before being killed.
The injured students were taken to hospital for treatment, officials said.
In a separate attack, an Israeli border policeman was shot dead by Palestinian gunmen on the outskirts of Jerusalem.
A female colleague of the officer was also wounded in the incident at a checkpoint close to the Shuafat refugee camp.
Israeli Radio said a large number of police and soldiers were now searching for the militants in the surrounding area.
A spokesman for the Israeli Prime Minister, Ehud Olmert, denounced the violence.
"These terror attacks are an example of the brutality of Palestinian terror which Israel battles on a daily basis," David Baker told the Associated Press.