Israeli officials acknowledged Wednesday that the United States is "worried" about the buffer zone Israel intends to create in the Gaza Strip. "They're afraid of a buffer zone," said one diplomatic official. "They're afraid there will be collateral damage." He stressed that Israel was taking all necessary measures to avoid harming innocent Palestinian civilians. To that end, Israel dropped leaflets in Gaza Tuesday evening warning residents to stay away from Kassam rocket launchers. Israel recently announced that it intended to mark out a "no-go" zone in northern Gaza to prevent Kassams from bombarding southern Israel as they have in recent days. The IDF has already undertaken a series of air raids, attacking Gaza roads to disrupt the network of launchers. Following those actions, the United States said the Israeli strikes were a justified response to the rocket attacks. "We see it in the context of failure to address the security situation" by the Palestinians, State Department spokesman Adam Ereli said. He also stated, "What we would like to see is effective measures against such acts so that the measures Israel is taking are not necessary." The Israeli officials said the US backing for the air strikes essentially indicated that the US would prefer Israel to continue with its policy of targeted attacks rather than create a buffer zone.