Attacks began in 2001. Since then (August 2014 data), almost 20,000 rockets have hit southern Israel, all but a few thousand of them since Israel withdrew from the Gaza Strip in August 2005. Hamas justified these as counter-attacks to the Israeli blockade of Gaza. The rockets have killed 28 people and injured hundreds more. The range of the rockets has increased over time. The original Qassam rocket has a range of about but more advanced rockets, including versions of the old Soviet Grad or Katyusha have hit Israeli targets from Gaza.