JERUSALEM — A much-awaited United Nations report into the 2014 Gaza war released Monday found that both Israel and Palestinian militant groups may have committed war crimes during the conflict.
The commission said it gathered ‘‘substantial information pointing to serious violations of international humanitarian law and international human rights law’’ by both sides. In some cases, it added, these violations may amount to war crimes.
‘‘The extent of the devastation and human suffering in Gaza was unprecedented and will impact generations to come,’’ said Mary McGowan Davis, the chair of the commission. ‘‘There is also ongoing fear in Israel among communities who come under regular threat.’’
The war started July 8, 2014, after a series of events that began with the kidnapping and killing of three Israeli teenagers in the West Bank, as well as the subsequent kidnapping and killing of a Palestinian teenager in an apparent revenge attack. Israel responded to the teens’ kidnapping by arresting hundreds of Hamas members in raids in the West Bank, prompting militant groups in Gaza to step up their rocket attacks.
More than 2,200 Palestinians, including hundreds of civilians, were killed during the fighting, according to U.N. and Palestinian officials, while 73 people, including six civilians, died on the Israeli side.
Israel, which long has had a contentious relationship with the United Nations, preemptively criticized the report as biased. In particular, Israel took issue with the U.N. Human Rights Council that commissioned the inquiry, saying it is stacked with countries that focus disproporiate attention on Israel while having poor human rights records themselves.
Palestinian officials and Hamas had no immediate comment.
Israel’s Foreign Ministry said it was studying the full U.N. report, but noted ‘‘it is well known that the entire process that led to the production of this report was politically motivated and morally flawed from the outset.’’ It said the UNHRC ‘‘has a singular obsession with Israel, passing more country specific resolutions against Israel than against Syria, Iran and North Korea combined — in fact, more than against all other countries combined.’’
A report by the council into the 2008-2009 war, conducted by South African jurist Richard Goldstone, found evidence that Israel and Hamas both committed war crimes, though Goldstone later backed off his key allegations against Israel.
Israel has attacked the council’s latest investigation since it was ordered last July. Israeli claims of bias forced the head of the investigation, Canadian law professor William Schabas, to resign earlier this year after it was discovered he had provided legal advice to the Palestine Liberation Organization.
The commission, which presented its findings in Geneva, said the 2014 hostilities saw a huge increase in firepower, with more than 6,000 airstrikes by Israel and approximately 50,000 tank and artillery shells fired. Palestinian armed groups fired 4,881 rockets and 1,753 mortars toward Israel during the 50-day war, it said.
Palestinians have said that the Israeli army violated the rules of war, which include giving adequate warning to civilians, using proportionate force and distinguishing between civilians and combatants. They have pointed to the high civilian casualty count as evidence.
Israel claims that Hamas is responsible for the civilian casualties because it used Gaza’s residents as ‘‘human shields’’ by firing rockets from residential areas and operating in schools, hospitals and mosques. It also notes that Hamas’ rockets and mortar shells were aimed at Israeli population centers.
Israel has argued that it took unprecedented measures to avoid civilian casualties, ordering residents to evacuate through leaflets, phone calls, radio broadcasts and warning strikes with unarmed shells ahead of live airstrikes.
In advance of the U.N. report, Israel released a report compiled by a group of retired Western military officers who found that Israel met or ‘‘significantly exceeded’’ the international laws of war. The report was sponsored by the ‘‘Friends of Israel Initiative,’’ a pro-Israel group of retired politicians and diplomats from around the world.
In its conclusions, the U.N. commission said Israel ‘‘released insufficient information regarding the specific military objectives of its attacks.’’
It says it recognizes the dilemma Israel faces in releasing information that would disclose in detail the targets of military strikes. ‘‘Be that as it may, security considerations do not relieve the authorities of their obligations under international law. The onus remains on Israel to provide sufficient details on its targeting decisions to allow an independent assessment of the legality of the attacks,’’ it wrote.