Israeli soldiers of the 155mm artillery cannons unit fire towards the Gaza Strip from their position near Israel's border with the coastal Palestinian enclave, on July 21, 2014. World efforts to broker a ceasefire in war-torn Gaza gathered pace as Israel pressed a blistering 14-day assault on the enclave, pushing the Palestinian death toll to 558. AFP PHOTO/MENAHEM KAHANA (Photo credit should read MENAHEM KAHANA/AFP/Getty Images)

Among the difficult reports streaming in from Gaza over the past few weeks, two especially painful events have captured my attention.

The first was the shelling of a UN school building in Jabaliya, where a number of families that had escaped or been forced to flee their homes had taken refuge. At least 15 civilians were killed, and dozens more wounded. Israel argued they were targeting an area from which fire had been directed at Israeli forces.

The second was the bombing of a bustling market in the Shuja'iya neighborhood. At a time of precious few opportunities for civilians to safely buy food and other vital supplies, 16 people were killed and around 200 were wounded. Shops, stalls and merchandise were burned or destroyed.

Harsh criticism of Israel followed each incident but -- as in the past -- Israel defended its actions, arguing that it was targeting militants and doing its best to avoid civilian casualties.

I served as a crew commander in the Israeli artillery corps at the beginning of the Second Intifada, and I feel compelled to counter this claim from Israel. The images, evidence and army reports from recent operations in Gaza -- of more than 1,900 deaths (a number which will likely increase by the time you read this) and a large amount of the population left without shelter -- show that Israel has deployed massive artillery firepower. Such firepower is impossible to target precisely.

Artillery fire is a statistical means of warfare. It is the complete opposite of sniper fire. While the power of sharpshooting lies in its accuracy, the power of artillery comes from the quantity of shells fired and the massive impact of each one.

In using artillery against Gaza, Israel therefore cannot sincerely argue that it is doing everything in its power to spare the innocent.

The truth is artillery shells cannot be aimed precisely and are not meant to hit specific targets. A standard 40 kilogram shell is nothing but a large fragmentation grenade. When it explodes, it is meant to kill anyone within a 50-meter radius and to wound anyone within a further 100 meters.

Furthermore, the humidity in the air, the heat of the barrel, and the direction of the wind can all cause unguided shells to land 30 or even 100 meters from where they were aimed. That is a huge margin of error in somewhere as densely packed as Gaza.

The imprecision of this weaponry is so great that Israeli forces are compelled to aim at least 250 meters away from friendly troops to ensure their safety -- even if those troops are sheltered. In military terms, this distance is called the "safe range of fire."

In 2006, when shelling was first used against the Gaza Strip, the "safe range of fire" for Palestinian civilians was reduced from 300 to just 100 meters. Shortly afterwards, a stray shell landed inside the home of the Ghabeen family in Beit Lahiya, killing a young girl, Hadeel, and wounding other members of her family.

In response to this and similar tragedies, human rights organizations appealed to the Israeli High Court of Justice to cease this lethal practice, and in June 2007 the Attorney-General announced that no more artillery fire was to be used in the Gaza Strip.

But just a few years later, during Operation Cast Lead, extensive artillery fire was again aimed at the heart of the Gaza Strip. And up until the recent ceasefire, throughout Operation Protective Edge, Israel has fired thousands of artillery shells into Gaza -- causing intolerable harm to civilians and widespread destruction, the extent of which will only be fully exposed when the fighting ceases.

It's true that in at least some cases, the army has informed civilians of its plans to attack a certain area and advised them to leave. But this in no way excuses the excessive damage and huge toll on civilian lives.

I write this with great sorrow for civilians hurt on both sides. Sorrow for our soldiers who have fallen in this operation, and sorrow for the future of my country and the entire region. I know that as I write, soldiers like me have fired shells into Gaza.

They had no way of knowing who or what they would hit.

Faced with so many innocent casualties, it is time for us to state very clearly: this use of artillery fire is a deadly game of Russian roulette. The statistics, on which such firepower relies, mean that in densely populated areas such as Gaza, civilians will inevitably be hit as well. The IDF knows this, and as long as it continues to use such weaponry, it will be hard to believe when it claims to be minimizing civilian deaths.

As a former soldier and an Israeli citizen, I feel compelled to ask today: have we not crossed a line?

Idan Barir served in the Israeli artillery corps during the Second Intifada and is a member of Breaking the Silence