Human Rights Watch called on Israel on Thursday to investigate seven incidents in which it said Israeli troops shot and killed Palestinian civilians who were flying white flags during the war in the Gaza Strip in January.

Expressing disappointment with Israel's response so far to a range of allegations of war crimes made by international bodies, the New York-based lobby group said governments should press for prosecutions under international law if Israel and its enemies in Gaza's Islamist authorities did not act themselves.

In a response to the report, the Israeli military said its soldiers were obligated to avoid harming anyone waving a white flag but that in some cases Hamas militants had used civilians with white flags for cover.

"Any person who displays a white flag in this way acts illegally, does not enjoy protection from retaliatory action, and endangers nearby civilian populations," the military said.

In correlation with the statement, the IDF uploaded a video to the internet depicting what it said was a Hamas gunman planting an explosive device and then attempting to take shelter in a home of uninvolved civilians waving white flags during fighting in Gaza.

In the latest report from various organizations to catalogue accusations of possible war crimes by both sides in three weeks of fighting, Human Rights Watch said it had statements and other evidence indicating 11 unarmed people including five women and four children were shot dead while in groups waving white flags.

"These casualties comprise a small fraction of the Palestinian civilians wounded and killed," Human Rights Watch said. "But they stand out because, in each case, the victims were standing, walking or in slowly moving vehicles with other unarmed civilians, and were trying to convey their non-combatant status by waving a white flag."

"All available evidence indicates that Israeli forces were in control of the areas in question, no fighting was taking place there at the time, and no Palestinian forces were hiding among the civilians or using them as human shields."

A Gaza observer group put civilian deaths at more than 900 out of more than 1,400 Palestinians it said were killed, while Israel said just under 300 civilians and some 900 fighters were killed.

Thirteen Israelis, 10 soldiers and three civilians, died.

Israel has rejected international criticism of an offensive it said was launched to curb rocket attacks on its towns by Hamas in Gaza. It says it is investigating allegations but has not yet found cause to prosecute any of its soldiers.

Human Rights Watch, which said it had received no reply to detailed questions it sent the army, gave an account of an allegation that on Jan. 7 a soldier shot dead two children.

"Two women and three children ... were standing in front of their home after an Israeli soldier ordered them outside -- at least three of them holding pieces of white cloth -- when a soldier near a tank opened fire, killing two girls, ages 2 and 7, and wounding the third girl and their grandmother," it said.

Defence Minister Ehud Barak has repeatedly insisted Israel has "one of the most moral armies in the world."