Here's a more detailed account from a reporter on the spot in the London broadsheet The Independent At least 10 dead as US soldiers fire on school protest

Strikes me as a scrupilously fair report, giving both sides, but also pointing out inconsistencies. For exmple:

According to Lt-Col Eric Nantz, the troops were being shot at and stones had been thrown. They tried to disperse the crowd with loudspeaker warnings but in vain, he said. Under threat, they fired back.

Yet there are no bullet holes visible at the front of the school building or tell-tale marks of a firefight. The place is unmarked. By contrast, the houses opposite – numbers 5, 7, 9, and 13 – are punctured with machine-gun fire, which tore away lumps of concrete the size of a hand and punched holes as deep as the length of a ballpoint pen. Asked to explain the absence of bullet holes, Lt-Col Nantz said that the Iraqi fire had gone over the soldiers' heads. We were taken to see two bullet holes in an upper window and some marks on a wall, but they were on another side of the school building.