• Victims found with up to six gunshot wounds • Israel 'about to lose a friend' warns Turkey's US envoy

The autopsy results released today by the Turkish authorities after the Israeli attack on the Gaza flotilla reveal in chilling detail the intensity of the military force unleashed on the multinational convoy.

Each of the nine victims on the Mavi Marmara in international waters off the coast of Israel in the early hours of Monday morning was shot at least once and some five or six times with 9mm rounds.

The results also reveal how close the fighting was. Dr Haluk Ince, chair of Turkey's council of forensic medicine (ATK), said: "Approximately 20cm away was the closest. In only one case was there only one entrance wound. The other eight have multiple entrance wounds. [The man killed by a single shot] was shot just in the middle of the forehead with a distant shot."

The details emerged as Turkey warned that it may reconsider its diplomatic ties with Israel unless it receives an apology.

The deputy prime minister, Bulent Arinc, warned: "We may plan to reduce our relations with Israel to a minimum."

Namid Tan, the ambassador to Washington, warned that Israel was "about to lose [a] friend". He repeated calls for an independent investigation of the raid and end its blockade against Gaza.

Asked if Turkey might break off relations, he said: "We don't want this to go to that point." But he added: "The government might be forced to take such an action."

Speaking at the funeral of the youngest activist, prime minister Tayyip Erdogan accused Israel of betraying its religion. "You killed 19-year-old Furkan Dogan brutally. Which faith, which holy book can be an excuse for killing him?" he asked.

According to the scientists at the ATK, Dogan, who held US and Turkish citizenship was shot five times – from close range in the right side of his nose, in the back of the head, in the back and twice in the left leg.

The oldest victim was 60-year-old Ibrahim Bilgen, a Turkish politician, engineer and activist who was married with six children. He had been shot once in the right temple, once in the right side of his chest, once in the back and once in the hip.

Cetin Topcuotlu, a 54-year old former Taekwondo champion who worked as a coach for the Turkish national team, was shot three times – once in the back of his head, once in his hip and once in his belly. His wife, Cigden, who was with him on the Mavi Marmara said at his funeral on Thursday she would take part in further flotillas to Gaza with her son.

The detail of the wounds came as yet more survivors returned to the UK and gave their account of the attacks.

In a hastily arranged press conference in central Londonshortly after his Turkish airlines plane touched down at Heathrow, Ismail Patel, the 47-year-old chairman of the Friends of al-Aqsa, condemned what he called "the cold-blooded murder and killing of our colleagues". He said: "These deaths were avoidable and I lay the blame squarely with the Israelis."

Israel has previously said its troops had been left with no choice after they came under attack from activists armed with knives and iron bars when they were dropped by helicopter on to the ship.

Patel claimed that as soon as the Israeli Defence Force helicopter appeared above the Mavi Marmara, "it started using immediately live ammunition" without any warning being issued.

After the first victim fell the white flag was raised, he said, but Israeli forces continued firing. "I think the Israeli soldiers were shooting to kill because most of the people who died were shot in the top part of their bodies," he said. He believed that later victims were injured in their legs after a "tactical move" by the commandos to wound rather then kill.

Alex Harrison, a Free Gaza activist who was on the smaller Challenger yacht, which was crewed mainly by women, said the Israelis used rubber bullets, sound bombs and tasers against them.

"Two women were hooded, they had their eyes taped," she said, describing how the yacht was quickly overwhelmed. "We stood and tried to obstruct the armed, masked men and maintained no other defence and still they used violence."

Harrison, 32, from Islington, north London, also witnessed the Mavi Marmara being stormed from above by helicopter and said the Israelis started firing before their troops touched down on the boat.

"I have seen some selective footage that the Israelis have chosen to put out suggesting that we responded with violence," she said. "You must remember that these are unarmed civilians on their own boat in the middle of the Mediterranean. People picked up what they could to defend themselves against armed, masked commandos who were shooting."

The violence was "initiated by the Israelis on a massive scale," she said, adding she was pleased her colleagues on the Rachel Corrie, an Irish vessel, were continuing to Gaza this weekend.

"I am thrilled they are going," she said. "They know exactly what risks they face. They are doing what our government's haven't and I thank them."

Both Harrison and Patel criticised the British authorities for failing to provide sufficient consular assistance while the activists were detained in an Israeli prison in Beersheva.

Patel said he was not visited by anyone from the British mission and Harrison said the consul told her that Israeli officials had prevented him visiting captured Britons.

"I did see the British consul," Harrison said. "He told me that he had sitting outside the prison all day ... asking for access and not been given it. I see that as an insult from Israel to the British, that they were denying the British consul the right that citizens have. I also see it as a sign that the British don't have the strength to stand up to Israel."

Foreign Secretary William Hague confirmed that a total of 34 of the activists on the aid flotilla were British, with all but two of them having been sent to Turkey by the Israeli authorities.

In Gaza City, the de facto Hamas prime minister, Ismail Haniyeh, told crowds of worshippers at Friday prayers that Israel's blockade was in its final stages.

"Now not only Gazans speak of the blockade, but also the [UN] security council and the international community. Everyone is demanding the siege be lifted."

The nine victims

Cengiz Alquyz, 42

Four gunshot wounds: back of head, right side of face, back, left leg

Ibrahim Bilgen, 60

Four gunshot wounds: right chest, back, right hip, right temple

Cegdet Kiliclar, 38

One gunshot wound: middle of forehead

Furkan Dogan, 19

Five gunshot wounds: nose, back, back of head, left leg, left ankle

Sahri Yaldiz

Four gunshot wounds: left chest, left leg, right leg twice

Aliheyder Bengi, 39

Six gunshot wounds: left chest, belly, right arm, right leg, left hand twice

Cetin Topcuoglu, 54

Three gunshot wounds: back of head, left side, right belly

Cengiz Songur, 47

One gunshot wound: front of neck

Necdet Yildirim, 32

Two gunshot wounds: right shoulder, left back