In international conflicts, civilians may not be used to protect areas from military operations. (Convention IV, Art. 28 and Protocol I, Art. 51, Sec. 7)
1. Civilian objects shall not be the object of attack or of reprisals. Civilian objects are all objects which are not military objectives as defined in paragraph 2.
2. Attacks shall be limited strictly to military objectives. In so far as objects are concerned, military objectives are limited to those objects which by their nature, location, purpose or use make an effective contribution to military action and whose total or partial destruction, capture or neutralization, in the circumstances ruling at the time, offers a definite military advantage.
3. In case of doubt whether an object which is normally dedicated to civilian purposes, such as a place of worship, a house or other dwelling or a school, is being used to make an effective contribution to military action, it shall be presumed not to be so used. ( (Protocol I, Art. 52, Sec. 3)
So the PA violated the Geneva Conventions by using women as human shields as well as by using a mosque as a military base. Israel was justified in fighting back against the terrorists in the mosque as there was no doubt that they were shooting from the mosque.
Not to mention the terrorists who disguised themselves as women, violating international law that says that combatants be in uniform.