JERUSALEM — The Israeli military said Wednesday it has closed its investigation into the shelling deaths of 21 members of a single Palestinian family and would not file any charges in what was one of the gravest incidents in the 2009 war in the Gaza Strip.

The military's move, which exonerates Israeli soldiers from any responsibility in the killings, outraged relatives of the killed Palestinians and the Israeli human rights group that had pressed for the investigation. They said the findings proved the army is not capable of investigating the conduct of its soldiers.

"We are talking about a crime against civilians," said Salah Samouni, 34, whose 2-year-old daughter was killed when Israeli shells slammed into the Gaza City house where the family had gathered.

"We know that God above will punish the killers. If they escaped trial, they can't escape God's punishment," said Samouni, who survived the shelling.

Israel launched the three-week offensive in Gaza in response to months of rocket fire by the ruling Hamas militant group. About 1,400 Palestinians were killed in the fighting, including hundreds of civilians, and thousands of buildings were destroyed or damaged. Thirteen Israelis also died.

Surviving members of the Samouni family had claimed the family was ordered by Israeli soldiers to take refuge in a house that was then shelled, killing 21 people.

Israel has argued that Hamas was responsible for civilian deaths during the fighting, saying the militant group used schools, homes and mosques for cover while attacking Israeli troops.

In its findings, the Israeli military said its investigation "totally refuted" allegations that the incident was a war crime. It denied the building was deliberately targeted or that soldiers acted recklessly.

Following the war, a U.N. report accused Israel of deliberately attacking civilians in its campaign against Hamas militants. The report's lead author, South African jurist Richard Goldstone, later questioned that finding, although the report was never modified or withdrawn.

The report also accused Hamas militants of targeting Israeli civilians, and said that both sides may have committed war crimes.

B'tselem, an Israeli human rights group, said it was "intolerable" that the military exonerated itself of responsibility in the Samouni case. The military's response "demonstrates yet again the need for an Israeli investigation mechanism that is external to the army."

The Israeli military has filed three indictments against soldiers who took part in the operation, and in three other cases, disciplinary action alone was taken.

Hamas, which opposes peace with Israel, has run Gaza since seizing control of the territory from the rival Palestinian group Fatah in 2007. The Fatah-dominated Palestinian Authority, which is backed by the West and seeks peace with Israel, governs the West Bank.

Peace talks between Israel and the Palestinian Authority collapsed during the Gaza war in 2009, and have remained frozen due to disagreements over Israeli settlement construction. The Palestinians refuse to negotiate while Israel continues to expand settlements in the West Bank and east Jerusalem, occupied territories that the Palestinians claim for a future state.

The Palestinians delivered a letter to Israeli Prime Minister Benjamin Netanyahu last month outlining their conditions for restarting talks.

An Israeli official said Wednesday that Netanyahu's chief envoy, Yitzhak Molcho, would meet with Palestinian President Mahmoud Abbas next week to deliver Israel's response. Palestinian officials said the meeting would likely take place next Wednesday or Thursday at Abbas' West Bank headquarters. The officials all spoke on condition of anonymity pending an official announcement.