Israel is expected to reject calls from the United Nations and others for an international investigation of its deadly raid on a Gaza-bound aid flotilla.

Israelis stage a protest on Monday outside Turkey's embassy in Tel Aviv against Turkey's support for the Gaza-bound ships. ((Ronen Zvulun/Reuters))

At least nine people were killed when six ships trying to break the three-year blockade of Gaza were raided by Israeli commandos early Monday.

Israel says the commandos used force only after activists on board a Turkish flagship attacked them. Nine of the activists were killed.

Turkey, an unofficial backer of the flotilla, has accused Israel of committing a "bloody massacre" against civilians delivering humanitarian aid.

The UN's assistant secretary general, Oscar Fernandez-Taranco, said Monday in his briefing to the Security Council that the bloodshed would have been avoided "if repeated calls on Israel to end the counterproductive and unacceptable blockade of Gaza had been heeded."

Israel's military is already investigating the raid.

An official in the prime minister's office said there is "no case in recent history" where a democratic country's army involved in the deaths of civilians in an overseas operation has been subjected to an international investigation.

The government is expected to announce its refusal formally later in the day.

The raid prompted international criticism and fresh calls to lift the blockade of Gaza, although the details of what happened during the military raid are still not entirely clear.

Canadian Farooq Burney was on board the ship that was attacked.

He said the Israeli navy approached the boat at dawn on Monday and threw a smoke bomb onto it. The smoke bomb exploded, causing people to yell and scream, he said. Then commandos descended from a helicopter above and boarded the boat.

"When the commandos came in, the people on the boat started spraying them with water because they did not want them to get on the ship," Burney told CBC News. "And when the people in the helicopter came, they obviously had guns with them and they were, you could say were ready for action, and at that point [it] turned to hand-to-hand combat."

New flotilla underway

Pro-Palestinian activists say they are organizing a new flotilla to try to break Israel's blockade of Gaza in early fall.

Palestinians burn an Israeli flag on Monday during a protest against Israel's interception of Gaza-bound ships. ((Mohammed Salem/Reuters))

And an Irish-owned cargo ship is already steaming toward Gaza, expected to arrive as early as this weekend.

The MV Rachel Corrie is believed to be carrying 11 passengers, a much smaller contingent than the 700 activists believed to have been on Monday's flotilla.

It is carrying 1,000 tonnes of aid, the Belfast Telegraph reported Thursday.

Israel insists it, too, will be stopped.

The 10,000 tonnes of aid from the original flotilla, organized by the Free Gaza movement, remains stuck at the Israel-Gaza border.

Israel had been keen to show it would let the aid in as promised. But a Hamas government minister said the aid would not be let through until all of the protesters on board the flotilla are released from custody without exception.

Israel has deported 527 activists from countries including Greece and Turkey. Activists from Australia, Ireland and Italy remain in custody, as do a number of Israel citizens who had been on board the ships.

Free Gaza Movement spokeswoman Greta Berlin said her group is working with the European Campaign to End the Siege to send at least three aid ships to Gaza in September or October.

Turkish Islamic charity IHH is welcome to join the flotilla, despite Israel's allegation the group has terror ties, she said.