Rocket and mortar attacks by Palestinian militant groups during last summer's conflict in Gaza amounted to war crimes, Amnesty International says.
Militants displayed a "flagrant disregard" for the lives of civilians during the 50-day war, a report found.
Six civilians in Israel and 13 Palestinians are believed to have been killed as a result of such attacks.
Hamas, which dominates Gaza, said Amnesty's report contained many inaccuracies and false allegations.
The conflict left a total of at least 2,189 Palestinians dead, including more than 1,486 civilians, according to the UN. On the Israeli side, 67 soldiers were killed along with the six civilians.
'Circle of fear'
According to UN data, more than 4,800 rockets and 1,700 mortars were fired from Gaza towards Israel between 8 July and 26 August. Around 224 projectiles are believed to have struck Israeli residential areas.
Amnesty said that all the rockets used by Hamas and other militant groups, some of which have ranges of up to 160km (100 miles), were unguided projectiles which could not be accurately directed at specific targets and were "inherently indiscriminate".
The majority of Israel's 8.3 million people live within reach of the long-range rockets, and the report pointed out that as a result the "circle of fear has widened" in Israel.
Mortars are also imprecise munitions which Amnesty said should never be used to attack military targets located in or near civilian areas.
Four-year-old Israeli Daniel Tregerman was killed when a mortar launched in Gaza by Hamas' military wing, the Izz al-Din Qassam Brigades, struck a car parked outside his family's home in Kibbutz Nahal Oz on 22 August and sent shrapnel flying.
Amnesty said rocket fire had also endangered Palestinian civilians.
The group said an independent munitions expert had concluded that a Palestinian rocket had exploded next to a supermarket in the al-Shati refugee camp in Gaza City on 28 July, killing 13 civilians, 11 of them children aged between seven and 14.
Some Israeli attacks during the conflict also amounted to war crimes, Amnesty added. The group has previously accused the Israeli military of killing scores of Palestinian civilians in attacks targeting houses full of families, and of destroying high-rise buildings with no justification.
"Palestinian armed groups, including the armed wing of Hamas, repeatedly launched unlawful attacks during the conflict," said Amnesty's Middle East and North Africa director, Philip Luther.
"In launching these attacks, they displayed a flagrant disregard for international humanitarian law and for the consequences of their violations on civilians in both Israel and the Gaza Strip.
"The devastating impact of Israeli attacks on Palestinian civilians during the conflict is undeniable, but violations by one side in a conflict can never justify violations by their opponents."
Amnesty's report also detailed other violations of international humanitarian law by Palestinian groups during the conflict, such as storing rockets and other munitions in civilian buildings, including UN schools, and cases where armed groups launched attacks or stored munitions very near locations where hundreds of civilians were sheltering.
Hamas spokesman Tahir al-Nounou told the BBC that the report was "based on the Israeli narrative".
"It contains a lot of inaccuracies and false allegations," he added. "The [Israeli] Occupation put troops in civilian areas and the [Palestinian] Resistance did not target the civilian population."
An Israeli government spokesman said Israel welcomed Amnesty's "highlighting of Hamas's war crimes, including the deliberate targeting of Israel's civilian population by thousands of rockets and mortars.
"Unlike Hamas, Israel is vigorously investigating its conduct, aiming to draw lessons and minimise civilian harm. Meanwhile, Hamas continues to incite terror attacks against Israeli civilians, boasts of building new cross-border assault tunnels and test-fires rockets, in preparation for further violence against Israelis," the official said.