Twenty one Israeli soldiers have been killed during intense fighting in Gaza, an Israeli military spokesman has said. The figure marks the highest number of Israeli soldiers killed in a single day since fighting began in the enclave. The IDF had announced the death of three other soldiers in Gaza on Jan. 22, taking the overall Israeli war toll to 219.Rear Admiral Daniel Hagari said Palestinian militants had fired a rocket-propelled grenade at a tank. At the same time, an explosion occurred in a two-storey building, causing it to collapse on the Israeli troops, he added.