Gaza City, Gaza Strip ? Israel’s three-day aerial bombardment of the Gaza Strip has killed dozens of civilians, along with Hamas fighters, and has paralyzed life in a territory already battered by blackouts and supply shortages during 18 months of border closures.

Israel has stressed that most of the deaths and injuries were Hamas fighters and says it’s careful to avoid harm to bystanders. But the nonstop attacks have caused widespread power outages, terrified residents and left aid agencies unable to feed thousands of needy people.

By Monday, the death toll rose to 364, with some 1,400 reported wounded, according to Palestinian medical officials.

The United Nations reported that at least 62 of the dead were women and children, and medics said eight children under the age of 17 were killed in overnight strikes.

Israel launched its campaign, the deadliest against Palestinians in decades, on Saturday in retaliation for rocket fire aimed at civilians in southern Israeli towns.

Israel, which has also allowed limited humanitarian supplies into the territory, is attacking Hamas-run organizations, homes of activists and security posts — all scattered in densely populated areas. Gazans say most strikes come without warning.

However, Israeli forces offered a general warning by dropping leaflets and recording brief announcements that interrupt radio broadcasts. They also reached other homes by telephone, telling Gaza residents to flee their homes if they were hiding weapons or militants.

“Civilian casualties are almost impossible to avoid, and that’s particularly true when so many locations are being targeted,” said U.N. humanitarian chief John Holmes.

U.N. Secretary-General Ban Ki-moon again condemned what he called Israel’s excessive use of force and urged an immediate cease-fire.

Holmes said as much as 80 percent of Gaza’s 1.5 million people “are more or less dependent on food aid from the outside.”