JERUSALEM (AP) — More force should have been used to clear a ship's deck before the deadly May raid on a pro-Palestinian flotilla, Israel's army chief said Wednesday, claiming that some of the Turkish activists on board had guns and opened fire first, in the most detailed account of the incident to date.

Lt. Gen. Gabi Ashkenazi said an Israeli commando was shot in the stomach as he rappelled down to the Mavi Marmara, forcing him to return fire. A forensic examination of bullet remnants recovered did not match Israeli weapons, he said, calling it proof that the activists had guns and were prepared to use them.

Speaking to an official Israeli inquiry into the raid, Ashkenazi said the military underestimated the level of violence it would encounter and should have done more to ensure "sterile conditions" on the ship's deck — indicating more force was needed to subdue pro-Palestinian activists before soldiers boarded the vessel from helicopters overhead.

The charity behind the flotilla has insisted that its activists were not carrying firearms.

Israeli commandos killed nine Turkish activists, including one American dual national, in the May 31 raid on the Mavi Marmara, which was trying to breach Israel's blockade of the Gaza Strip. The soldiers have said they opened fire after coming under attack by a mob of activists wielding clubs, axes and metal rods. The activists have said they were defending themselves.

A military video of the operation showed activists wearing body armor and gas masks and using a circular power saw to cut through a ladder soldiers were trying to use to board the ship from a rubber dinghy.

After that attempt failed, Ashkenazi said commandos then used stun grenades to clear the deck area before rappelling down from helicopters. The army has said activists beat and stabbed the troops and even fired shots. With their lives in danger, the soldiers responded with gunfire and killing the activists, Ashkenazi said.

"We should have ensured sterile conditions in order to dispatch the forces in a minimum amount of time," Ashkenazi testified, saying snipers should have been used to provide cover for the rappelling soldiers. "It would have lowered the risk to our soldiers but it would not have prevented the tension."

The bloodshed drew widespread international criticism and has pushed Israel to loosen its restrictions on Gaza. But a tight naval blockade remains in place. Israel says the measures, imposed after the violent Hamas movement took control of Gaza in 2007, are needed to prevent arms from reaching Hamas.

During his three-hour-long testimony, Ashkenazi said the imperfect execution was partly due to the military not knowing enough about the IHH — the Turkish Islamic charity that sponsored the flotilla. Israel has outlawed the group because of its ties to Hamas.

He said the Turkish activists on board opened fire first, and that Israeli troops responded appropriately, first with non-lethal means and only later with live fire. He said the outcome would have been far more deadly were it not for their restraint. "The soldiers justifiably opened fire. They opened fire at those they needed to, and didn't at those they didn't need to," he said.

Ashkenazi's testimony followed that of Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak.

In their testimonies, the prime minister tried to shift some of the responsibility toward Barak, while the defense minister indicated the military did not execute the plan properly.

Ashkenazi in contrast shouldered the responsibility for all military conduct.

The Israeli commission is headed by a retired Supreme Court justice and includes two foreign observers: David Trimble, a Nobel peace laureate from Northern Ireland, and Brig. Gen. Ken Watkin, Canada's former chief military prosecutor.

Although the panel does not have the authority to punish Israeli leaders, its findings could be politically damaging.

Israel's military has already wrapped up its own investigation, and the United Nations launched another probe of its own on Tuesday.

In a related development, Israel's Army Radio obtained video footage that it said showed an Arab Israeli lawmaker walking among men holding metal rods aboard the ship before the soldiers arrived. Hanin Zoabi has previously claimed she never saw any weapons aboard the vessel.

Zoabi was later branded a "traitor" by some fellow parliamentarians, who voted to revoke some of her government privileges.

Zoabi maintained her innocence to Israel Radio on Wednesday. "The tape doesn't mean anything, it's a minute out of an hour and a half of hostilities," she said. "I didn't see armed people, I didn't see people with clubs, I didn't see people with knives."