Victoria-based activist Kevin Neish was aboard one of the vessels in a Gaza-bound flotilla that was stormed by Israeli troops on Monday. (CBC)

A Victoria-based activist who was aboard a Gaza-bound vessel that was stormed by Israeli troops claims Israeli commandos instigated the violence, saying they began opening fire on people on the deck.

"The first gunfire that we knew about was when the Israeli helicopter opened fire on people on the deck," Kevin Neish, a self-described human shield, told CBC News from Istanbul.

Neish, 53, was one of three Canadians and hundreds of activists taken into custody during the raid on a flotilla that was challenging Israel's three-year-old blockade on the Hamas-ruled Gaza Strip. Israeli commandos stormed the boats in international water. Nine activists were killed and hundreds arrested.

Neish was near the stern of the main vessel when it was stormed, about 15 metres from Israeli soldiers as they climbed aboard and battled the activists. He disputed Israeli claims that the activists were armed. He said that once the attack began, people were looking for objects with which to defend themselves.

"It was a bloodbath and there were bodies strewn about, and medical attention given to them and a number of people with holes in their heads and it was pretty dramatic, but I did not see a weapon, a gun, anywhere on the Turkish, Arab, humanitarian-aid side," Neish said.

"They were using chains, lengths of pipes, sticks, against the machine-guns," he said.

Israel says activists fired first

Israeli officials have rejected the claims of activists that Israeli soldiers initiated force, saying troops acted in self-defence. They said they did not expect resistance when they boarded the ships.

Israel has also released video showing soldiers descending onto the boat from a helicopter as crowds of men appear to attack them with pipes.

Israeli officials said their troops only returned gunfire after they were shot at by some of the activists who had wrestled away the guns of at least two soldiers.

Neish saw Israelis use grenades, tear gas

Neish said he was on the first deck near the stern of the vessel as the attack began and was about 15 metres from Israeli soldiers who were trying to board, using sound grenades and tear gas. He said the activists and aid workers forced them back.

He later found out that, at the same time, more commandos were rappelling from a helicopter onto the third deck near the bridge.

"When they repelled the folks down below, I understand the machine-guns on the helicopter started to shoot people on the deck," said Neish.

"I was within 50 feet of the initial attack by the Israeli soldiers. I saw the flash grenades and the tear gas happening right in front of me, but there was no gunfire from the ship. It was attack from the Israelis. And then I was up top and from that point on, it was dead bodies of the Turks coming in and injured bodies of the Turks and the second deck mezzanine area … was literally full of wounded and dying humanitarian aid workers."

Neish said he didn't directly witness the outbreak of gunfire but stressed that he didn't see any guns among the activists and aid workers before the attack began.

"Before the attack, I walked around the ship about an hour before and what they had was nuts and bolts and pieces of pipe around the edge of the ship to throw at the Israeli Zodiacs. That's the weapons I saw [with] the activists: I saw links of chain and nuts and bolts, wooden links."

Saw 2 captured soldiers

Neish said that he saw two captured Israelis being carried from the upper deck down. He said one man tried to strike out and attack one of the young soldiers but other activists pushed him back and protected the soldier.

"I didn't see any serious wounds on the soldiers and they were flailing about, terrified, but I didn't see any wounds on them," he said.

Neish said around six to eight people began disarming the soldiers, pulling weapons off their ammo belts and taking their backpacks and helmets.

"They were released unharmed, from what I understand."

He said after he was taken into custody, Israeli authorities treated him poorly and he is still suffering the effects of his arrest.

"I spent 15 hours without being allowed to go to the washroom. I spent 24 hours without really being allowed to stand," he said. "I had guns put in my face. I had a revolver put in my face. Anytime I tried to rise up, stretch, I had a gun on me, had a dog snapping at me."

Neish said the Turkish government has offered to fly him home.