As I write this I can hear the waves of the Mediterranean shift and gently crash at Gaza’s shore. The sky is clear, the moon is bright and if not for the loud buzzing of an Israeli drone it would be soothing.

In a place as densely populated as Gaza, the sea offers a rare sense of space. When the weather is warm and the Israeli gunships are far, Palestinians come to the beach to escape. They spill from the cinder block warrens of the city for the shore, and look out at the only side of Gaza that is not a heavily fortified border.

For the Bakr boys, a pack of scrawny kids of fishermen, the sea was also their playground. They would jump in the waves, play hide-and-seek among the fishing boats and collect scrap metal near the port. The sort of stuff a boy does when he lives in Gaza.

During Israel’s air offensive the past nine days, the boys -- all cousins -- had avoided the beach. Missiles and shells have been fired at the shore before but according to relatives, today the boys wanted to play.

It is unclear whether the assault came from the air or the sea. I was sitting outside our hotel, at the back overlooking the port, and watched the first shell or missile hit a shipping container on the jetty.

It spewed some brownish smoke but there was no secondary explosion or fire. I saw some people running away from it and wondered: Was anybody hit?

According to witnesses, the boys were running up the beach toward the al Deira hotel, which right now is full of foreign journalists. People on the terrace yelled at the boys to run toward them to safety. They were trying... until the second explosion.

The boys fell to the sand, bleeding. At least one died instantly, others were carried by hotel staff or whoever could run fast enough to help them. Journalists like Peter Beaumont of The Guardian administered first aid. You can read his first-hand account here.

I walked quickly through our hotel to the street out front and heard the ambulances coming. One. Two. A third raced by. Down the street I could see a crowd forming. I ran toward it.

On the beach they had the dead boys on stretchers. They were loaded and taken away. The images of the boys’ mothers learning of their loss are shattering.

The IDF released a statement saying it would “carefully investigate” what happened. It said the shipping container -- which I am told was repurposed as a registration hut for fishermen -- was the target.

On Twitter, an Israeli journalist cited IDF sources that said the boys, ages 9 to 11, were “misidentified” as fleeing fighters.

The IDF says it uses care to avoid civilian casualties. It has even released video showing missile strikes that have been called off because civilians are too close to the target.

It becomes a more awkward position to defend when four boys are killed on a beach directly in front of hotels full of foreign journalists.

Just over an hour after the cousins were killed, relatives gathered around their bodies at the mosque for their funeral. The boys had played together, they had died together and they would be buried at the same time. They were wrapped in flags. They looked small on the stretchers. They still had sand from the beach on their feet.