UNITED NATIONS, May 31 (Reuters/Louis Charbonneau and Patrick Worsnip) - The UN Security Council met in emergency session on Monday to discuss Israel's storming of a Gaza-bound aid flotilla, with most members of the 15-nation body calling for a thorough investigation.

Following a 90-minute open meeting, the council went into closed-door consultations. Diplomats said envoys were haggling over the text of a proposed statement by the council, a task that dragged on into the evening.

Israeli marines stormed a Turkish aid ship bound for Gaza on Monday. The incident, in which the Israeli military said at least nine pro-Palestinian activists were killed, sparked widespread condemnation.

Many council members criticized the Israeli action with varying degrees of vehemence, and said it was time for Israel's three-year-old blockade of Hamas-controlled Gaza to be lifted.

This is tantamount to banditry and piracy, Turkish Foreign Minister Ahmet Davutoglu told the council. It is murder conducted by a state. Most of those who died in the incident were Turks, according to one senior Israeli officer.

The United States, Israel's principal ally on the council, spoke in guarded terms. Deputy UN Ambassador Alejandro Wolff said Washington regretted the loss of life and wanted a credible and transparent investigation by Israel.

But he criticized the attempt by the flotilla organizers to attempt to run Israel's blockade of Gaza. Direct delivery (of aid) by sea is neither appropriate nor responsible and certainly not effective under the circumstances, he said.

REQUEST OF TURKEY

Israel's deputy ambassador, Daniel Carmon, told the council the flotilla was anything but a humanitarian mission. Its organizers cynically used the guise of humanitarian aid to send a message of hate and to implement violence, he said.

The organizers, some of whom he said were linked to terrorist organizations, had forced Israel to launch its operation, which had been intended as a preventive measure to counter illegal breakage of the blockade, Carmon said.

British Ambassador Mark Lyall Grant said there was an unambiguous need for Israel to act with restraint and called the blockade of Gaza unacceptable and counterproductive.

Diplomats said points at issue in the proposed council statement included whether an investigation should be independent -- a word that could preclude just a probe by the Israeli military -- and how to assign blame for the incident.

The council session was convened at the request of Turkey and Lebanon, both of which are rotating nonpermanent members of the council.

The permanent Palestinian observer to the United Nations, Riyad Mansour, told reporters before the meeting that he wanted to see a decisive outcome, a reaction (that will) bring Israel to account ... to condemn this action.

Mansour represents the Palestinian Authority, which has no control over the Gaza Strip, as it is de facto governed by the militant group Hamas.

Israel's blockade of Gaza has been criticized by UN officials for causing what they call a humanitarian crisis. But Carmon said, There is no humanitarian crisis in Gaza.