United Nations: Israel used "excessive and unreasonable" force on a Turkish-led flotilla carrying humanitarian aid to Gaza in which nine people were killed, a UN inquiry committee has said, even as it justified Tel Aviv's blockade of the Palestinian territory.

The 105-page report found that when Israeli commandos boarded the main ship 'Mavi Marmara' they faced "organised and violent resistance from a group of passengers" and therefore used force in self-defence. It said the use of force was "excessive and unreasonable."

The report however said that Israel's blockade of Gaza is legal as it faces threat to its security.

"Israel faces a real threat to its security from militant groups in Gaza," the report says. "The naval blockade was imposed as a legitimate security measure in order to prevent weapons from entering Gaza by sea and its implementation complied with the requirements of international law."

Terming the loss of life as unacceptable, it said Israeli military's treatment of passengers was also abusive, a report in the New York Times, which obtained a copy of the UN report, said.

The UN investigation, led by former New Zealand prime minister Geoffrey Palmer, recommends that Israel should make "an appropriate statement of regret" and pay compensation.

It says Turkey and Israel should resume full diplomatic relations "repairing their relationship in the interests of stability in the Middle East."

Eight Turkish nationals and an American of Turkish descent were killed in the May 31, 2010 raid, which led to widespread international criticism of Israel.