'Civil order' collapse in Gaza warned

World steps up calls for desperately needed aid in area amid heavy fighting

GAZA STRIP — Palestinians in northern Gaza reported fierce air and artillery strikes on Monday as Israeli troops backed by tanks pressed into the enclave with a ground operation that prompted more international calls for civilians to be protected.

Hamas said on Sunday that it was engaged in "heavy fighting" with Israeli troops inside northern Gaza, as besieged residents were again warned to flee southward. The Israeli army said on Monday that its forces killed "dozens" of militants in clashes through the night.

The United Nations warned that "civil order" was starting to break down in Gaza after thousands of people ransacked its food warehouses there, taking wheat, flour and other supplies.