In a clear sign that Hamas is adopting Hizbullah tactics, IDF troops uncovered underground Kassam launch silos inside the Gaza Strip during an early-morning foray there on Thursday. During the operation, the troops killed seven Palestinian gunmen affiliated with Hamas and Islamic Jihad. Pictures released by the IDF Spokesperson's Office showed two underground Kassam rocket silos, a meter in diameter and two meters deep. The launchers, the army said, were big enough to hold a Kassam or Grad-model Katyusha rocket that could be launched by remote control. The IDF estimates that there are additional underground rocket silos throughout the Gaza Strip. The silos were discovered by the Golani Brigade's elite Egoz Unit and defense officials said that their discovery proved the need for continued ground operations inside the Gaza Strip. Some 20 Kassam rockets hit the western Negev on Thursday. One of the rockets hit a garage adjacent to a house in Sderot, causing a fire and sending three people into shock. Two Kassams landed near a college in the Eshkol region. No one was wounded and no damage was reported. The other rockets all hit open areas. Jpost.com staff contributed to this report.