Palestinian gunmen killed one Israeli and injured at least three others in two incidents on Sunday night.
The first took place close to Hebron in the post-1967 territories.
Eyewitnesses say four gunmen opened fire from a vehicle on a group of border police officers.
They killed one and injured three lightly.
The Aq’sa Martyrs Brigades wing of Yassir Arafat’s Fatah organization says it carried out the attack.
It said it was in return for Israel’s killing a week ago of the leader of Hamas in Gaza ‘Abd Al-‘Aziz A-Rantisi.
Some 90 minutes later it is believed Palestinians opened fire on a Bedouin north of Hebron, close to the Jewish town Efrat.
The Israeli citizen was a guard in the area.
Doctors described his condition as serious.
The Aq’sa Martyrs Brigades claimed it was behind the attack, but the Israeli military said it is investigating various possibilities.