On 22 March '11, the Israeli military fired "Keshet" mortar shells at the Shaja'iya neighborhood east of Gaza City. The shells killed four Palestinian civilians, three of them from the same family, including two children. The media reported that the firing was a response to Palestinian firing at southern Israel a short time earlier.
Mortar shells have a wide deviation range. "Keshet" mortars are more precise than other kinds of mortar shells, but their deviation range is still several dozens of meters wide. In the densely populated Gaza Strip, such a range can cause grave harm to civilians. Indeed, the use of "Keshet" mortars has already killed non-combatant civilians in the past. During Operation Cast Lead in the Gaza Strip, several such shells landed in a dense urban area next to the al-Fakhura school in Gaza City, killing 32 civilians who were not taking part in the hostilities, including 11 members of a single family.
A report regarding investigations into Operation Cast Lead, released in July 2010 by Israel's Foreign Ministry, stated that following the al-Fakhura school incident, and as part of Israel's effort to minimize harm to Palestinian civilians, Israel's judge advocate general had recommended formulation of more stringent definitions in military orders to govern the use of mortars in areas populated by civilians. The report also stated that the chief of staff had ordered the undertaking of staff work to draft the required orders.
These statements demonstrate that the highest military echelons are aware of the problematic nature of mortar shells. However, the results of the mortar shelling on 22 March raise fear that in spite of the clear statements in the report, the military has not implemented the recommended changes.
One of the fundamental principles of international humanitarian law is the principle of distinction, which obliges the parties in conflict to distinguish between legitimate military targets and civilian targets. One consequence of this principle is the prohibition on using a weapon that cannot distinguish between targets. Firing mortar shells at a populated area, such as the shells that killed the four Palestinian civilians on 22 March, does not meet this principle and is therefore illegal.
Deliberate targeting of civilians by armed Palestinian groups constitutes a grave breach of the laws of war, and Israeli security forces must act to protect Israeli civilians from such attacks. Launching such attacks from within populated Palestinian areas in Gaza is also illegal and adds insult to injury. However, these violations by Palestinian groups do not justify the violation of the principle of distinction by Israel.