Israel's official government watchdog issued a long-awaited report Tuesday in which it found the military was ill-prepared to counter the threat of underground tunnels used by Hamas militants from Gaza during the 2014 war, and that the Cabinet was not provided enough information to make proper decisions about it.

The state comptroller's report found faults in both the military and government, unleashing immediate infighting over who was to blame. While the report added to a growing list of political headaches for Prime Minister Benjamin Netanyahu, it did not appear to pose any immediate threat to him.

The report found that the military was aware of the vast underground tunnel network Hamas had built well ahead of the war, but did not properly assess its threat. As a result, forces were not prepared to deal with them and had to improvise without the necessary intelligence and preparation.

On the political level, the comptroller found that Netanyahu and then-Defence Minister Moshe Yaalon considered the tunnels to be a "strategic threat" but did not convey this to the rest of the decision-making Security Cabinet.

"It would be proper for the Cabinet to first outline the strategic goals and then, based upon that, the military prepare its operational plans to achieve those goals," the report read.

The war was the culmination of a chain of events in the summer of 2014 that began on June 12 when Hamas militants kidnapped three Israeli teenagers who were hitchhiking in the West Bank.

Israel retaliated by arresting several hundred Hamas members in the West Bank, leading the group to fire dozens of rockets into Israel from its Gaza stronghold. The bodies of the missing teens were discovered on June 30, and with rocket fire intensifying, Israel launched its Gaza assault on July 7.

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An Israeli army officer gives journalists a tour of a tunnel said to be used by Palestinian militants for cross-border attacks, in July 2014. (Jack Guez/Reuters)

Infiltrated through tunnels

During 50 days of fighting, more than 2,200 Palestinians, over half of them civilians, were killed according to UN and Palestinian figures, along with 74 people on the Israeli side. Israel has disputed that death toll saying many militants were counted as civilians.

The Israeli military's "Iron Dome" defence system proved largely effective in knocking down incoming projectiles fired by Hamas. But Hamas militants managed to infiltrate through tunnels into Israeli territory several times, killing at least 11 soldiers. Some 10 days into the fighting, Israeli ground forces moved into Gaza with the stated aim of destroying the tunnels.

In a statement, Netanyahu called the operation a "great success." He said "about 1,000 terrorists" were killed and thousands of rockets destroyed and pointed to the "unprecedented quiet" along the Gaza border since the fighting ended. Israel is acting "thoroughly, responsibly and quietly" to implement the "significant lessons" of the operation, Netanyahu said.

Although Israel claimed to have destroyed 32 tunnels during the fighting, Tuesday's report found numerous flaws in the operation. Among its findings: Only half of the tunnels were completely destroyed.

'Not properly prepared'

Yair Lapid, leader of the opposition Yesh Atid party and a member of the Security Cabinet during the war, said the report showed that the country, under Netanyahu's leadership, "was not properly prepared" for the war.

"The report proves beyond any doubt that the prime minister knew about the strategic threat of the tunnels, didn't order the IDF to prepare an operational plan, didn't inform the Security Cabinet and didn't tell the public the truth," Lapid said.

But Education Minister Naftali Bennett, another member of the Security Cabinet, directed most of his criticism at Yaalon and the military chief at the time, Benny Gantz, saying the military was ill-prepared and took too long to take action against the tunnels.

"I don't think Bibi should quit because of this," Bennett said, using Netanyahu's nickname. "I think lessons should be learned and they are I have to say."

Bennett was among the few decision makers to be portrayed favourably by the report. Bennett said he learned of the tunnel threat independently and brought up the issue at a June 30 Cabinet meeting, before the war had broken out. He said it took the army some 10 days to return with a plan to counter them.

He accused the military of being "very reluctant" to go into Gaza, and when it did, it made the mistake of destroying tunnel entrances before ground troops arrived. That turned the troops into "sitting ducks," he said, as they dug through rubble to destroy the tunnels. He estimated that roughly 30 soldiers were killed during the anti-tunnel operation.

"I view this in a sense as a march of folly," Bennett told reporters.

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A Palestinian man stands next to the remains of a house, which witnesses said was destroyed in an Israeli air strike, in Rafah in the southern Gaza Strip in August 2014. (Ibraheem Abu Mustafa/Reuters)

Massive underground wall

Since the war, Israel has discovered several other tunnels and destroyed them. The military claims it has improved its technology to detect tunnel activity, and the Defence Ministry has begun construction of a massive underground wall meant to block the tunnels as well.

The Israeli military said it is studying the report and "implementing lessons learned."

In Gaza, Hamas spokesman Fawzi Barhoum accused Israel of committing "war crimes" in the fighting.

"This government is a government of terrorism using all kinds of killing against Palestinian civilians," he said. "All those who committed crimes against the Palestinian people and against the civilians in the Gaza Strip must be prosecuted at the International Criminal Court."

The ICC has opened a preliminary investigation into Israel's actions during the war.

Tuesday's report could help Israel fend off the investigation. Before opening a full-fledged war crimes investigation, one of the ICC's criteria is whether a country is capable of investigating itself and prosecuting its own citizens.