JERUSALEM — Prime Minister Olmert of Israel spent hours yesterday testifying before the commission investigating Israel’s conduct during its much-criticized war in Lebanon over the summer.

The Winograd commission was appointed in the fall to try to reconstruct the government’s decisions during the war with Lebanon’s Hezbollah guerrillas and to determine if anyone should be censured.

The government has been criticized for failing to meet its two main objectives — destroying Hezbollah and returning two Israeli soldiers whose capture by the guerrillas sparked the war. Reserve soldiers returning from the battlefield also complained of poor preparations and lack of food and ammunition.

Israel’s army chief, Dan Halutz, recently resigned his post after months of criticism, and there have been widespread calls for the other wartime leaders, Mr. Olmert and Defense Minister Amir Peretz, to follow suit.

Mr. Olmert was the last witness called before the commission, following a parade of top Cabinet ministers and military officers. His testimony was made in a closed hearing.

The Israeli daily Ha’aretz said Mr. Olmert was expected to be asked about his decision to go to war after Hezbollah militants captured the two Israeli soldiers in a July 12 cross-border raid, as well as his war aims and his conduct of the fighting.

Ha’aretz said he was expected to defend his conduct and to assert that Israel emerged victorious from the war, an impression that many Israelis disagree with.

The war killed between 1,035 and 1,191 Lebanese civilians and combatants, according to tallies by government agencies, humanitarian groups, and the Associated Press.

A total of 120 Israeli soldiers were killed in fighting, and 39 civilians were killed by Hezbollah rockets fired into northern Israel during the conflict.

The fighting ended in an August 14 cease-fire brokered by the United Nations.

The commission is expected to issue an interim report in mid-March.