Israeli Prime Minister Benjamin Netanyahu said Tuesday that the army had launched an investigation into the “disaster” that led to the deaths of 21 soldiers in Gaza a day before. “The IDF (Israeli army) has launched an investigation of the disaster. We must learn the necessary lessons and do everything to preserve the lives of our warriors,” Netanyahu said in a statement. The 21 reservists were among a total of 24 soldiers killed in Gaza on Monday, the army’s biggest single-day losses since the start of its ground operation on October 27, military spokesman Daniel Hagari said.