premise: Palestinian militant groups continued on Saturday launching homemade rockets from northern Gaza Strip at Israel as a revenge for killing their fellow members last week.
  Israel Radio reported that two rockets landed at an Israeli army base near the Erez Crossing early Saturday, causing two explosions, but no injuries had been reported.
  Al Aqsa Martyrs Brigades, armed wing of the ruling Fatah movement, has claimed responsibility for the rocket attack, said the report.
  Meanwhile, residents of central Israel have expressed fear that militants would fire rockets from the West Bank at their towns, and called the Israeli army to station early alarming system in their areas.
  Heads of local councils in areas between the West Bank and Tel Aviv in central Israel met with Israeli Defense Minister Shaoul Mofaz and asked for taking serious measures against firing rockets, said the radio.
   What led to the launching of rockets in the Gaza Strip?
hypothesis: two rockets landed at an Israeli army base