Activists returning to Europe after Israeli forces raided their aid flotilla said last night that the commandos had beaten passengers and used electric shocks during the assault.
Six Greeks and several others, including a Turkish woman and her one-year-old baby, were released yesterday, but Israel has barred access to hundreds of other people seized during the raid that killed at least nine and wounded dozens early on Monday morning.
Most of those killed were aboard the Turkish-flagged 'Mavi Marmara', and there have been conflicting accounts of what happened during the assault.
Turkish activist Nilufer Cetin, who had hidden with her baby, Turker Kaan, in her cabin's bathroom, told reporters that she believed there were 11 dead.
"The ship turned into a lake of blood," Ms Cetin told reporters in Istanbul, having returned after Israeli officials warned that jail would be too harsh for her child.
She said she was aware of the possible danger of joining the trip but "there are thousands of babies in Gaza. If we had reached Gaza we would have played with them and taken them food".
She said Israeli vessels "harassed" the flotilla for two hours starting at around 10pm on Sunday, and returned at around 4am on Monday, firing warning shots and telling the ships to turn back.
"When the 'Mavi Marmara' continued on its course the harassment turned into an attack," said Ms Cetin.
"They used smoke bombs followed by gas canisters. They started to descend on to the ship with helicopters." The clashes that then erupted were "extremely bad and brutal".
She added that the Israeli authorities had taken their telephones and laptops.
Her husband, Ekrem Cetin -- the ship's engineer -- was still being held by the Israelis last night.
Some 400 Turkish activists were on the six-ship flotilla, along with more than 30 Greeks and people of some 20 other countries including Germany, the US and Russia.
The ships had been trying to break the three-year blockade of Gaza to deliver humanitarian aid, the activists said.
Dimitris Gielalis, who had been aboard the 'Sfendoni', said the attack happened very suddenly.
"Suddenly, from everywhere we saw inflatables coming at us, and within seconds fully equipped commandos came up on the boat," said Mr Gielalis, one of six Greeks who was deported from Israel yesterday.
"They came up and used plastic bullets. We had beatings, we had electric shocks," he said.
He claimed the boat's captain was beaten for refusing to leave the wheel, while a cameraman filming the raid was hit with a rifle butt in the eye.
The returning Greeks said those still in custody were refusing to sign papers demanded by the Israeli authorities.
"During their interrogation, many of them were badly beaten in front of us," said Aris Papadokostopoulos, who was aboard the 'Free Mediterranean' that was travelling behind the 'Mavi Marmara'.
Mr Papadokostopoulos said the flotilla was about 130 kilometres off Gaza when the raid occurred.
Aboard the other boats, he said, commandos beat activists, but nobody was gravely injured.
He said no one put up resistance on the 'Free Mediterranean', which was carrying a cargo of wheelchairs, building material and medical and pharmaceutical aid.
Crew member Mihalis Grigoropoulos said he was on the bridge of the 'Free Mediterranean' and heard shooting coming from the Turkish ship.
Several people who tried to stop the Israeli forces from getting to the bridge were hit by electric shocks and plastic bullets, he said. "We didn't resist at all. Even if we had wanted to, what could we do?"