UNITED NATIONS (AFP) – The UN Security Council called Tuesday for an impartial investigation into the Israeli attack against a flotilla carrying humanitarian aid to Gaza, and the immediate release of all civilians.

The statement came at the end of an emergency session that lasted more than 12 hours, pitting Turkey against the United States in calling for a strong and specific condemnation of Israel, diplomats said.

In the end, the statement read by council president Claude Heller, Mexico’s ambassador the United Nations, condemned “those acts which resulted in the loss of at least 10 civilians and many wounded.”

“The Security Council took note of the statement of the UN Secretary General on the need to have a full investigation into the matter and it calls for a prompt, impartial, credible and transparent investigation conforming to international standards,” the statement said.

The statement fell short of a call for an independent investigation, with the United States backing an Israeli investigation.

“We have every confidence that Israel can conduct a credible and impartial and transparent, prompt, investigation internally,” Alejandro Wolff, the deputy permanent US representative, said.

Israeli commandos carried out the pre-dawn raid Monday in international waters on a convoy of vessels carrying activists from a variety of countries who were bringing food and medical supplies to Gaza to circumvent an Israeli blockade.

Accounts of what happened conflicted. Israeli officials said the commandos acted in self defense after being attacked with clubs and knives, while activists charged that the commandos fired on sleeping civilian passengers.

The Security Council requested the immediate release of all ships and civilians held by Israel. Israeli public radio earlier reported, however, that Israel would hold 480 of the activists and expel 48 others.

“The Council urges Israel to permit full consular access, to allow the countries concerned to retrieve their deceased and wounded immediately and to ensure the delivery of the humanitarian assistance from the convoy to its destination,” the statement said.

The council reiterated its grave concern over the humanitarian situation in Gaza, which it said was “not sustainable.”

It stressed the need for a “sustained and regular flow of goods and people to Gaza as well as unimpeded provision and distribution of humanitarian assistance throughout Gaza.”

Emphasizing that the only viable solution to the Israeli-Palestinian conflict was a two state solution, the statement expressed concern that the incident occurred at a time when indirect talks were underway between the sides.

It urged the parties “to act with restraint, avoiding any unilateral and provocative actions, and all international partners to promote an atmosphere of cooperation between the parties and throughout the region.”

The closed door negotiations on the statement followed a public debate in the council, during which Israel was vehemently attacked by Turkey, the country from which the flotilla departed. Many of those aboard the convoy were Turkish nationals.

In individual statements made ahead of the emergency session, almost all 15 council members condemned the Israeli assault.

“It is clearer than ever that Israel’s restrictions on access to Gaza must be lifted in line with Security Council Resolution 1860. The current closure is unacceptable and counterproductive,” British Ambassador Mark Lyall Grant said.

France, Russia and China — also veto-wielding permanent council members — also called for the blockade to be lifted and for an independent inquiry.

The United States, Israel’s traditional ally which often uses its veto power to shield the Jewish state — did not request specifically that Israel end its blockade on the Gaza Strip. But it hinted that the measure at least should be eased.

Wolff said Washington was “deeply disturbed by recent violence and regrets tragic loss of life and injuries. We are working to ascertain the facts.”

Israel’s UN envoy Daniel Carmon, meanwhile, insisted that the flotilla was not on an aid mission.

“What kind of peace activists use knives, clubs and other weapons to attack soldiers who board a ship in accordance with international law?” Carmon said.

But Turkish Foreign Minister Ahmet Davutoglu told delegates that Israel had “lost all legitimacy” through the deadly raid.

“It is murder committed by a state. It has no justification whatsoever,” he said.