With mounting concern about the hundreds of civilians killed, nine Israeli human rights groups wrote to their government warning of their "heavy suspicion ... of grave violations of international humanitarian law by military forces".

Among the sites hit yesterday was Sheikh Radwan cemetery. Thirty graves were destroyed, spreading rotting flesh over a wide area . The army said it was targeting a nearby weapons cache.

So far 1,010 Palestinians have died, including 315 children and 95 women, Dr Moawiya Hassanein, head of Gaza's medical emergency services, told the Guardian. The number of injured after 19 days of fighting stood at 4,700, he said. On the Israeli side, 13 people have died, among them three civilians, and four soldiers accidentally killed by their own troops.

The Palestinian Centre for Human Rights, which is based in Gaza and has field staff across the territory, believed at least 673 civilians had been killed - about two-thirds of the total. A more accurate count of civilian deaths is difficult, with journalists and international human rights observers banned from entering Gaza.