JERUSALEM — The human rights group Amnesty International said Wednesday that Israel had displayed “callous indifference” and in some cases committed war crimes when it bombed scores of homes of suspected militants, sometimes killing entire families, during last summer’s war in Gaza.

The attacks on family homes of suspected operatives was the signature tactic of the 50-day Israeli campaign against Hamas and allied militant groups in the Gaza Strip in July and August.

Israel’s declared aims of the war, which included bombardments from land, sea and air, followed by a ground offensive, were to stop rocket fire at Israel and destroy networks of tunnels, some of which reached into Israel.

The Israeli Foreign Ministry dismissed the Amnesty International report as biased, saying that it ignored war crimes by Hamas, including “the use of human shields, as well as ammunition storage and firing at Israeli civilian population centers from within schools, mosques and civilian neighborhoods in Gaza.”

More than 2,100 Palestinians were killed in the conflict, about 70 percent of them civilians, according to the United Nations. On the Israeli side, 73 soldiers and civilians were killed in combat, and in rocket and mortar strikes.

The 49-page report documented eight cases in which family homes were attacked without warning, causing the deaths of at least 104 civilians, including 62 children.

Philip Luther, Amnesty’s director for the Middle East and North Africa, said that the findings show a pattern of attacks in which Israeli forces showed “a shocking disregard for the lives of Palestinian civilians.”

“Israeli forces have brazenly flouted the laws of war,” he said, “displaying callous indifference to the carnage caused.”

The single deadliest attack documented in the report was a strike in which 36 members of four families, including 18 children, were killed when a three-story building was bombed. The second most lethal case was a strike in which 25 civilians, including 19 children, were killed when another house was leveled.

Amnesty International said it identified possible military targets in the first building, and a member of Hamas’ armed wing was outside the second, but “regardless of the intended targets, both of these attacks constitute grossly disproportionate attacks under international law” and should have been called off when it became clear that so many civilians were present.

The Israeli army said during the war that it had repeatedly warned Palestinians to leave combat zones, but Gaza residents said that no place was safe during the fighting in the crowded coastal strip, and that there was nowhere to flee.

In some cases, buildings were hit with warning rockets before being bombed, but others were struck without warning.