Updated

The U.N.'s top human rights official demanded Tuesday that all sides in the two-week war in the Gaza Strip refrain from indiscriminate attacks on civilians, warning that violations may amount to war crimes.

The warning by U.N. High Commissioner for Human Rights Navi Pillay came at a special session of the U.N.'s top human rights body, which voted 29-1 to authorize an international commission of inquiry to investigate alleged abuses since mid-June in the Gaza Strip.

Only the United States voted against the resolution championed by Arab nations. Another 17 of the Human Rights Council's 47 member-states abstained.

Israel said that the council's decision to investigate Israel's role in the conflict sent a message to extremist groups around the world that using human shields — which it accuses Hamas of doing — was an "effective strategy."

"The Human Rights Council must start to investigate Hamas' decision to turn hospitals into command bases and schools into weapons warehouses and to place rocket batteries near playgrounds, private homes and mosques," said a statement from the Israeli prime minister's office.

Of the more than 600 Palestinian deaths in the Gaza Strip reviewed by the United Nations, three-quarters were civilians, Pillay said. At least 147 were children and 74 women, she said.

According to the latest count more than 680 Palestinians and 31 Israelis — two of them civilians — have been killed during the conflict.

Pillay cited an Israeli drone missile strike in Gaza City that killed three children and wounded two others while they were playing on the roof of their home. She also made reference to an Israeli strike and naval shelling that struck seven children playing on Gaza beach, killing four from the same family.

"These are just a few examples where there seems to be a strong possibility that international humanitarian law has been violated, in a manner that could amount to war crimes," Pillay told the rights council's special session.

Israel launched its operation in Gaza on July 8 in response to heavy rocket fire out of Hamas-controlled Gaza. The fighting escalated last week with an Israeli ground offensive.

Pillay also warned that Hamas and others were violating international law.

"Israeli children, and their parents and other civilians, also have a right to live without the constant fear that a rocket fired from Gaza may land on their houses or their schools, killing or injuring them," Pillay said.

"The principles of distinction and precaution are clearly not being observed during such indiscriminate attacks on civilian areas by Hamas and other armed Palestinian groups," she added.

Pillay said not abiding by those principles could amount to war crimes and crimes against humanity.