Defense Minister Ehud Barak on Tuesday took "full responsibility" for Israel's deadly raid on Gaza-bound aid flotilla in May, saying the government had foreseen the potential for violence when it decided to launch the operation.

Testifying before an Israeli investigative committee - which foreshadows an impending United Nations probe - Barak said he accepted full responsibility for the instructions given to the military over its interception of six Gaza-bound ships.

"I carry overall responsibility for everything that took place in the systems under my command. I carry responsibility for the orders given on the political level," Barak told the panel headed by retired Supreme Court judge Yaakov Turkel.

But while holding himself accountable, the defense minister was quick to take aim at the Israel Defense Forces.

"The decision making process at the political level was not the reason for the reality that emerged at the end of the operation," Barak said, calling the move to intercept the ships "a reasoned decision by a group of senior cabinet ministers".

Barak said that on May 26, five days before the commando raid which left nine pro-Palestinian activists dead, a draft of the operation was presented to Prime Minister Benjamin Netanyahu's inner cabinet, known as the 'Forum of Seven'.

The outline included an intelligence assessment and a range of potential outcomes, including the possibility of 'extreme scenarios', Barak said.

Barak's testimony apparently contradicts Monday's testimony before the committee by Netanyahu, who said that discussions before the raid focused largely on the likely impact on public relations, while the chance of violent confrontation was mentioned only in passing.

According to the IDF, troops boarded the boats wielding non-lethal paintball guns and opened fire with live ammunition only when their lives were threatened by activists, who initiated the clash aboard the flotilla's lead ship, the Mavi Marmara.

During the Forum's discussions, IDF Chief of Staff Gabi Ashkenazi had expressed fear over the public reaction to the raid, Barak said.

Ashkenazi's fears were borne out when the attack drew international condemnation, leading to a near severance of ties with Turkey, Israel's traditional ally under whose flag the ships had sailed.

"In debates by the Seven, Ashkenazi stressed that it would not be simple but that we would do it," Barak said. "The politicians determined the 'what' and the IDF worked out the 'how' - and the IDF carried out the operation."