Israeli forces pounded Gaza Strip houses, mosques and tunnels on Monday from the air, land and sea, killing at least seven children and six other civilians, as they consolidated a bruising offensive against Palestinians, AP reported . A stream of diplomats and world leaders hoping to end the violence headed for the region to meet with Israeli leaders as world outrage over ballooning Palestinian casualties mounted. Gaza health officials reported 524 dead and nearly 2,000 wounded since Israel embarked upon its military campaign against Gaza's Islamic Hamas rulers on Dec. 27. At least 200 civilians were among the dead. Israeli forces seized sparsely populated areas in northern Gaza on Sunday and by Monday morning were dug in on the edges of Gaza City. Further movement into the heart of the built-up areas would mean deadly urban warfare, replete with house-to-house fighting, sniper fire and booby traps, in crowded streets and alleyways familiar to Hamas' 20,000 fighters. A total of 13 civilians died in the various attacks across Gaza on Monday morning, said Gaza health official Dr. Moaiya Hassanain.