JERUSALEM, (AP) -In a letter to the troops, Israel’s military chief acknowledged publicly for the first time Thursday that there were shortcomings in the military’s performance during the recent fighting with Hezbollah guerrillas in Lebanon.

Israel went into the monthlong war as a united front against Hezbollah, but since the fighting ended last week, the country has splintered into a cacophony of reproachful voices.

Criticism of the military’s preparedness and tactics swelled after the battles ended without a clear-cut victory for Israel. Questions about the wisdom of 11th-hour battles and reports of food and water shortages have fueled demands for a state inquiry into the war’s conduct and the resignation of Israel’s wartime leaders.

In a letter to Israeli fighters, military chief Lt. Gen. Dan Halutz wrote: “Alongside the achievements, the fighting uncovered shortcomings in various areas — logistical, operational and command. We are committed to a thorough, honest, rapid and complete investigation of all the shortcomings and successes.”

“Questions will be answered professionally, and everyone will be investigated — from me down to the last soldier,” according to the letter, released by the military Thursday.

War broke out July 12, hours after Hezbollah fighters killed three Israeli soldiers and captured two in a bold cross-border raid. About 160 Israelis — one-quarter of them civilians — died in the fighting, and northern Israel was all but paralyzed by nearly 4,000 rockets fired from across the border in Lebanon.

While Halutz was owning up to military missteps, the head of the Shin Bet security service was calling the war “a fiasco” in his first public statement on the fighting.

“The north was abandoned, the government systems collapsed there completely,” Shin Bet director Yuval Diskin told a closed security forum, according to meeting participants. “There were many failures, and the public sees and understands this. This is not the time to whitewash. The truth must be told. … Someone has to provide explanations and take responsibility.”

Prime Minister Ehud Olmert has acquiesced to calls for a war probe, and is expected to decide within days what kind of inquiry to conduct. The most sweeping inquiry would be a state commission, with powers to dismiss government and military officials.

A vocal group of reserve soldiers and bereaved parents has been demanding that Olmert, Halutz and Defense Minister Amir Peretz step down, or that the government conduct an honest reckoning of what went wrong by appointing a state commission of inquiry.

The war’s outcome has also unleashed a fierce spasm of political infighting. The governing coalition, established in May, has become even more brittle, with partners feuding over proposed budget cutbacks to pay for the war, which cost up to an estimated $9 billion.

Peretz — a former union boss with scant military experience — has especially come under fire, both within and outside his Labor Party. On top of having his credentials questioned, Peretz now faces a rebellion within his own party by members who oppose the budget cutbacks on the ground they would hurt Israel’s disadvantaged.

“Never has his leadership seemed more short-lived,” political writer Nadav Eyal wrote in Israel’s Maariv newspaper on Thursday.