JERUSALEM (CNN) -- Palestinian gunmen killed three Israelis and wounded five others in two separate shootings Sunday in the West Bank, Israeli medical services and security sources said.The Al Aqsa Martyrs Brigades claimed responsibility for both shootings. The group is a military offshoot of Fatah, the ruling party of the Palestinian Authority. Palestinian officials had no immediate response to the incidents.In the first incident, Palestinian gunmen killed three people and wounded four others, Israeli medical teams said. The attack occurred at a hitchhiking post in Gush Etzion junction, an area of Jewish settlements, officials said.In the other incident, Palestinians shot into a crowd of people walking near the entrance to the Eli settlement, north of Ramallah. One person was critically wounded, Israeli security and medical sources said.Separately, Israeli army troops shot an armed Palestinian during an operation near the city of Jenin in the northern West Bank, Israeli security sources said.Israeli media said the man -- a senior leader of Palestinian Islamic Jihad -- was killed, but Israeli security sources did not immediately confirm the reports.Palestinian Islamic Jihad, which operates from Gaza, is considered to be a terrorist organization by Israel and the United States.