Deputy Prime Minister Shimon Peres on Sunday called an IDF missile attack on Palestinian Authority Prime Minister Ismail Haniyeh's office in Gaza City overnight Saturday a "clear warning" to free kidnapped IDF soldier Cpl. Gilad Shalit. Peres said the attack on Haniyeh's office came "in the middle of the night," when Israeli officials knew Haniyeh would not be present. "It was a clear warning that he has to stop this double behavior," Peres told CNN's Late Edition. "Either it's a government with all the responsibilities of a government, or it's a terrorist organization, with all the consequences that stem from it." IDF aircraft, tanks and naval gunboats have been pounding Gaza for the past week in an effort to win the freedom of Cpl. Shalit, who was seized in a cross-border raid by Palestinian operatives last Sunday. Thousands of IDF troops were also sent into the coastal strip for Israel's first ground invasion since exiting Gaza nine months ago. Hamas, whose charter calls for Israel's destruction, took power after winning January parliamentary elections. "We are trying to topple the policies of this so-called government, which are policies of terror," Peres said. "The fact that they were once elected doesn't give them a license to shoot, to kill, to endanger, to kidnap Israeli people." Hamas has a military wing and a political wing, and its political leadership is divided between more moderate elements in the West Bank and Gaza, and the more radical top leadership based in Syria.