The parties agreed to a number of things. Coalition forces will allow
unfettered access to the Fallujah General Hospital to treat the sick
and injured. The parties also agreed to arrange for the removal and
burial of the dead and the provision of food and medicine in isolated
areas of the city. ...
Measures will also be put in place to facilitate the passage of official ambulances through the city, especially through checkpoints. Steps will also be taken to allow security, medical and technical personnel access to the city so they can work.
This would appear to confirm that U.S. forces, in the fighting, had in fact blockaded (if not bombed) the hospital and interfered with ambulances -- two of the more shocking charges featured in eyewitness accounts of the action there. I'm not enough of an expert to know what forms of assault on civilians constitute a formal war crime, but the people caught up in the fracas, or their fellow countrymen hearing about it from refugees and al-Jazeera, don't much care about formalities.
That said, negotiation with civil authorities is the sort of thing that we need to be doing more of. But damage has been done in all sorts of ways, the situation is still tense, and the latest news as I write is of renewed fighting in Fallujah and elsewhere...