Aqsa Martyrs Brigades, part of Palestinian President Mahmoud Abbas's Fatah faction, said they planned the attack together in response to Israel's killing of five Palestinian gunmen three days ago. The groups sent the bomber, 25-year-old Ayman Za'aqiq, from his village near the West Bank town of Hebron to carry out the attack in the nearby Israeli city of Beersheba, a spokesman for al-Aqsa Martyrs Brigades said. An Israeli police spokesman said nearly 50 people were treated at hospital, most of them for shock. The two guards, who chased the bomber, were critically hurt, the spokesman said. Israel killed five Palestinians during a raid in the West Bank town of Tulkarm on Thursday, drawing vows of revenge by armed Palestinian groups. --More 2207 Local Time 1907 GMT