The left-wing human rights organization B'Tselem wrote a letter to Defense Minister Amir Peretz on Friday, urging him to ensure that the IDF did not attack civilian targets in the Gaza Strip. The letter came in response to calls by several MKs to cut off Gaza's water and electricity. According to B'Tselem, intentionally harming civilian infrastructure constitutes prohibited collective punishment and could also constitute a war crime. In its letter, B'Tselem reminded the defense minister that Israel had bombed Gaza's only power plant about a year ago, leaving residents with a severely diminished electricity supply for months. "This act of vengeance did not stop the Kassam rocket fire," the organization noted. The group acknowledged that Kassam fire into Israel "is itself patently illegal and constitutes a war crime," and that "the Israeli government must act to defend its civilians from such attacks." However, the organization said, "the government cannot compensate for its failure to protect residents of Sderot by intentionally causing suffering in Gaza."