premise: Four Palestinians were wounded by Israeli troops' gunfire on Saturday night in the village of Qabatia, near the northern West Bank town of Jenin, Palestinian medics and security sources said.
  The sources said Israeli soldiers opened fire at a group of Palestinian teenagers in a raid on the village for wanted militants and injured four of them.
  An Israeli army spokesman said the troops opened fire at a group of stone- and firebottle-throwing Palestinian young men, aged between 13 and 15, and lightly wounded four of them.
  Meanwhile, the al-Aqsa Martyrs Brigades, armed wing of the ruling Fatah movement, claimed responsibility for launching two short-range homemade mortars from the Gaza Strip at Israel.
  The group said its militants fired the two mortar shells at the Israeli town of Kfar Azza, east of Gaza, in revenge for the Israeli assassination of the group's commander in northern Gaza last week.
   Why did the militants fire two mortar shells at Kfar Azza?
hypothesis: troops opened fire at a group