Israeli troops have entered a refugee camp called Jabaliya, sparking fierce fighting across the Gaza Strip area.
At least 31 people have been killed, and at least 130 injured, including Palestinian civilians and fighters, as well as Israeli soldiers and settlers.
The Israeli army says it's trying to stop Palestinian rocket attacks on Israeli towns, following an attack on a town which killed two Israeli children.
Israel's Prime Minister Ariel Sharon has now ordered more troops into Gaza.
Flattened buildings