* Activists deny firing guns seized from troops

* Israeli official says outnumbered troops fought to survive

* Desperate efforts to treat wounded at sea

(Adds detail and comment throughout)

By Simon Cameron-Moore and Yara Bayoumy

ISTANBUL/BEIRUT June 3 (Reuters) - Freed after days held incommunicado in Israeli jail, survivors of Monday’s storming of an aid ship described a “bloodbath”, with people shot before their eyes and desperate efforts to treat the wounded.

Those aboard the flotilla returned home on Thursday after being held in Israeli jail since the raid, at last able to give their own accounts of the incident in which Israeli troops killed nine activists aboard the cruise liner Mavi Marmara.

There were sharp differences in accounts: activists accused Israeli troops of war crimes, while Israel held to its line that they fired in self-defence. In one of the key differences, activists denied Israeli accusations that they fired first, with guns they had seized from Israeli troops in the melee.

All sides described a scene of confusion and mayhem in the botched assault.

“People had been shot in the arms, legs, in the head -- everywhere. We had so many injured. It was a bloodbath,” said Laura Stuart, a British housewife and first aider.

She described frantic attempts to treat the injured in a makeshift sick room on the ship, and failed attempts to resuscitate some of the dead.

FOUR ISRAELIS CAPTURED IN FIRST WAVE

Andre Abu Khalil, a Lebanese cameraman for Al Jazeera TV, gave an account that backed some of what both sides have said.

In his telling, activists initially wounded and captured four Israelis from a first wave that boarded the ship. A second wave of troops tried to storm the ship after the four were taken below decks.

“Twenty Turkish men formed a human shield to prevent the Israeli soldiers from scaling the ship. They had slingshots, water pipes and sticks,” he said. “They were banging the pipes on the side of the ship to warn the Israelis not to get closer.”

After a 10-minute standoff the Israelis opened fire.

“One man got a direct hit to the head and another one was shot in the neck,” he said. In all he saw some 40 people wounded, some to the legs, eye, stomach and chest.

One activist used a loudhailer to tell the Israelis the four captive soldiers were well and would be released if they provided medical help for the wounded activists. With an Israeli Arab lawmaker acting as mediator, the Israelis agreed. Wounded were brought to the deck and were airlifted off the ship.

Israel says its troops fired only after some of their weapons had been seized by activists, who fired first. “Once the soldiers saw knives, metal rods, chains, broken bottles, and they were shot at, they shot back and killed nine of them,” Israeli military spokesman Captain Ayre Shalicar said.

ACTIVISTS DENY FIRING

One of the organisers on board who returned on Thursday from an Israeli jail, Bulent Yildirim, chairman of the Foundation for Human Rights and Freedoms and Humanitarian Relief (IHH), said activists had indeed seized weapons, but never fired them.

“They were trying to land on the boat. So obviously there was this hand-to-hand combat and during that process the people on the boat were basically able to disarm some of the soldiers because they did have guns with them,” Burney told Reuters.

Asked if anyone had used the guns against the Israeli commandos, he said: “No, not at all.”

Canadian Farooq Burney, director of a Qatari educational initiative, said the commandos waited more than an hour before treating the wounded, even though activists had made a makeshift sign reading: “S.O.S. .. Please provide medical assistance.”

The 37-year-old Canadian said he witnessed one elderly man bleed to death before his eyes after being shot.

“He just passed out in front of us and we couldn’t see where he was hit so we opened up his lifejacket and we could clearly see that he was hit in the chest,” Burney said. “He was losing a lot of blood. It was on ... the right, just close to his chest and there was blood coming out from there. He passed away.”

The nine dead activists, who were brought home on Thursday in wooden coffins, were all Turks, including one dual U.S.-Turkish citizen. Yildirim said some activists were still missing, adding that an Indonesian doctor was shot in the stomach as he helped a wounded Israeli soldier.

“I took off my shirt and waved it, as a white flag. We thought they would stop after seeing the white flag, but they continued killing people,” Yildirim said. “A friend of ours saw two dead bodies in a toilet.”

British activist Sarah Colborne, of the Palestine Solidarity Campaign, said she was on deck when commandos approached in boats, “bristling with arms”. Others roped down from hovering helicopters and sound and gas bombs were let off.

“It looked like they were capable of killing anyone. They had obviously been fired up,” the 43-year-old told reporters.

“I saw one person who had been shot in the head between the eyes,” she said. “That made me realise how dangerous it was. That for me made me think they are using live ammunition, people are getting killed.” (Additional reporting by Alexandra Hudson and Allyn Fisher-Ilan in JERUSALEM, Christian Lowe in ALGIERS and Avril Ormsby in LONDON; editing by Peter Graff)