The U.S. group Human Rights Watch is urging Israeli leaders to thoroughly investigate reports that soldiers shot and killed civilians who were carrying white flags during Israel's 22-day assault on the Gaza Strip six months ago.

The report is the latest in a series of accusations that Human Rights Watch has made this year pointing to what the group says was the wrongful behavior of Israeli troops during the Gaza offensive.

Human Rights Watch Deputy Middle East Director Joe Stork tells VOA the report looked at seven incidents during the operation in which Israeli soldiers shot and killed 11 civilians, nine of whom were women and children.

"What sets these cases apart is that in these incidents, the individuals were waving white flags or were with a group of people holding, waving white flags to convey their civilian status," said Stork.  "Despite this, they were shot dead."

Israeli military officials say the army took many measures to safeguard civilians during the Gaza operation, that was targeted at Islamist militants who had been firing rockets over the border at civilians in southern Israel for years.

Israel Defense Forces spokeswoman Lieutenant Colonel Avital Leibowitz says the job of soldiers was complicated by what she says was the militants' use of civilians as human shields.

"We witnessed, in many cases, groups of civilians walking in the streets," said Leibowitz.  "Some of them were holding white flags, and amongst them were Hamas militants, armed with guns, with launchers.

Their goal was to move from one house to another house, because their tactic was to use those civilian homes as launching pads, really, little bases if you will."  

Leibowitz says the army continues to carry out investigations and has punished soldiers who were found to have misbehaved.

She questions the sourcing of the Human Right Watch report.

"The report is based, like the previous reports, is based on testimony of Palestinians that we are not sure how credible they are.  Their credibility has not been substantiated," she said.

Human Right Watch's Joe Stork says army investigators should launch a more thorough investigation.

"I can tell you that they have made no approach to the people involved in these seven incidents.  No approach whatsoever," he said.  "We checked with our contacts in Gaza, the families, the witnesses, in Gaza this week.  Here we are, half a year after the operation, the IDF has yet to contact anybody and say, 'would you be willing to cooperate?'"  

Palestinian officials and international organizations, quoting Palestinian figures, say about 1,400 people died during the 22-day Israeli assault on Gaza.