The rights group also accused Israel of continually violating human rights in the Gaza Strip. It cited Israel's ongoing economic blockade as violating international law, leaving Gaza residents without adequate food or water supplies
In its report, Amnesty lauded a United Nations commissioned report released last year by South African justice Richard Goldstone for highlighting Israeli violations during the war in Gaza. Goldstone's findings found both Israel and Hamas guilty of war crimes during the conflict.
"Israeli forces committed war crimes and other serious breaches of international law in the Gaza Strip during a 22-day military offensive codenamed Operation 'Cast Lead' that ended on 18 January (2009)," the rights group said.
"Among other things, they carried out indiscriminate and disproportionate attacks against civilians, targeted and killed medical staff, used Palestinian civilians as 'human shields', and indiscriminately fired white phosphorus over densely populated residential areas," it added. "More than 1,380 Palestinians, including over 330 children and hundreds of other civilians, were killed."
"In a display of counter political bias, the UN Human Rights Council, initially resolved to investigate only alleged Israeli violations," said the report. "To his credit, Judge Richard Goldstone, subsequently appointed to lead that investigation, insisted that the UN Fact-Finding Mission should examine alleged violations by both Israel and Hamas."
The group's report listed examples of what it said were war crimes committed by Israeli forces, but did not provide details of sources.
Amnesty's annual roundup of global human rights abuses urged members of the G-20 — a collection of major industrial countries and fast-growing developing countries — to set an example to the international community by signing up to the International Criminal Court.
The United States and others have refused to ratify the court's founding treaty partly because they fear the court could become a forum for politically motivated prosecutions of troops in unpopular wars like Iraq.
The U.S. State Department said in response to Amnesty's accusations that it "supports the need for accountability for any violations that may have occurred in relation to the Gaza conflict by any party."
"As we have said, the responsibility to address alleged abuses during the Gaza conflict lies with the Israelis and the Palestinians," the State Department said in a statement.
Israel earlier this year submitted a 46-page response to Goldstone's inquiry, which accused both Israel and Hamas of "grave breaches" of the fourth Geneva Convention.
In its report, Israel claimed its forces abided by international law throughout the war last year.