The Israeli army admitted that there had been “irregularities” in the use of cluster bombs during its deadly offensive in Lebanon last summer.

Defense Minister Amir Peretz ordered an “extensive inquiry” into the use of cluster bombs during the month-long offensive, which killed more than 1,200 Lebanese civilians, and displaced a million others.

Announcing the probe, Chief of Staff Lt Gen Dan Halutz said the use of cluster bombs during the conflict with Hezbollah was "disappointing".

"We must check whether the instructions were clear, I believe they were," Israel's Army Radio quoted him as saying.

Israeli army officials have previously insisted that they used cluster bombs only in accordance with international law.

Most experts believe that cluster munitions are “non-discerning” weapons that are prohibited from use in civilian areas.

Such weapons also have a high "dud" rate which leaves dangerous bomblets behind that can linger as threats for years.

Lt Gen Halutz claims that he banned the wide use of cluster bombs during the conflict.

But a commander of a Multiple Launch Rocket System (MLRS) battery told Haaretz newspaper that they used cluster bombs in several areas in southern Lebanon, adding that those sites had been described as "General Staff targets” because they were authorized by the chief of staff's office.

Moreover, sources in the defense minister's office said that Peretz had been informed that cluster bombs were used during the fighting.

MK Ran Cohen (Meretz), a reservist colonel who commanded an artillery battalion during Israel's first Lebanon war, said that the use of cluster bombs requires authorization by the division commander or higher. "This is a very serious matter," MK Cohen said. "If cluster bombs were used in populated areas, this constitutes an indescribable crime. There is no target that cannot be hit without cluster bombs. The massive use by the Israeli army of cluster bombs during the recent conflict suggests an absolute loss of control and hysteria."

Human rights groups say up to a million "bomblets" were left in populated areas in southern Lebanon after the fighting ended on August 14, following a UN-brokered ceasefire between Israel and Hezbollah.

So far, the UN's bomb disposal squad has discovered more than 58,000 unexploded bomblets at about 800 different locations in southern Lebanon. Most were found near populated areas.

Since the implementation of the truce, at least 22 Lebanese civilians, including many children, were killed and 134 others wounded by unexploded bomblets, according to Haaretz.

“We covered entire villages with cluster bombs, what we did there was crazy and monstrous,” the commander in the Israeli occupation forces’ MLRS (Multiple Launch Rocket System) unit told Haaretz.

In September, Haaretz reported that the Israeli army also used phosphorous shells in Lebanon.

International law bans the use of weapons that cause "excessive damage and unnecessary suffering," and many experts believe that phosphorous shells, which cause severe burns and a painful death, are included in this category.

Israel’s decision to investigate the wide use of cluster bombs in Lebanon came as two leading rights groups - Human Rights Watch and Amnesty International – issued reports criticizing it for firing cluster bombs into southern Lebanon, even in the final days of fighting, the BBC reported.

In its report, Amnesty International slammed Israel’s attacks in Lebanon as "indiscriminate and disproportionate", calling for a UN-led probe into the conduct of Israel and Hezbollah during the conflict.