Turkey's foreign minister warned Israel that it risks alienation among Arab nations by resisting an apology for last year's deadly raid on a Gaza-bound aid flotilla that killed nine pro-Palestinian activists. Uriel Sinai/Reuters

Turkey is preparing to challenge Israel's blockade on Gaza at the International Court of Justice, the foreign minister said Saturday, ratcheting up tensions between the once close allies.

Ahmet Davutoglu's comments came a day after Turkey expelled the Israel's ambassador and severed military ties with the country angered over its refusal to apologize for last year's deadly raid on a Gaza-bound aid flotilla that killed nine pro-Palestinian activists.

In an interview with Turkey's state-run TRT television, Davutoglu dismissed a UN report into the raid that said Israel's naval blockade of Gaza was a legal security measure. Davutoglu said the report — prepared by former New Zealand Prime Minister Geoffrey Palmer, and former Colombian President Alvaro Uribe, and presented to UN Secretary General Ban Ki-moon — was not endorsed by the United Nations and was therefore not binding.

"What is binding is the International Court of Justice," Davutoglu said. "This is what we are saying: let the International Court of Justice decide."

"We are starting the necessary legal procedures this coming week," he said.

'If Israel persists with its current position, the Arab spring will give rise to a strong Israel opposition.'—Turkish Foreign Minister Ahmet Davutoglu

The minister said the UN report released Friday contradicted an earlier report on the Gaza flotilla incident which found that Israeli forces violated international law when they raided the flotil

la. That report was prepared in September by three human rights experts appointed by the U.N.'s top human rights body.

Davutoglu also warned Israel that it risks alienation among Arab nations by resisting an apology.

"If Israel persists with its current position, the Arab spring will give rise to a strong Israel opposition as well as the debate on the authoritarian regimes," he said.

On Friday, Turkey downgraded diplomatic ties to the level of second secretary and gave the ambassador and other high-level diplomats until Wednesday to leave the country. In other measures against Israel, Turkey suspended military agreements, promised to back legal actions against Israel by the raid victims' families and vowed to take steps to ensure freedom to navigate in the eastern Mediterranean.

UN raid report shows Israel acted within its rights: PM's spokesman

Turkish officials refused to elaborate on the last move, but some analysts suggested Turkey could send navy vessels to escort aid ships in the future while Turkey's main opposition party on Friday warned such a step could lead to confrontation between Turkish and Israeli forces.

"The probability that [Prime Minister Recep Tayyip Erdogan's ruling] party has carried Turkey to the brink of a hot conflict is saddening and unacceptable," said Faruk Logoglu, a deputy chairman of the opposition Republican People's Party.

Earlier on Saturday, Ban urged Turkey and Israel to mend ties for the good of the Middle East peace process.

"I sincerely hope that Israel and Turkey will improve their relationship," Ban told reporters during a visit to Australia.

"Both countries are very important countries in the region and their improved relationship — normal relationship — will be very important in addressing all the situations in the Middle East including the Middle East peace process," he said, referring to a negotiated Palestinian-Israeli peace pact.

In Jerusalem, Prime Minister Benjamin Netanyahu's spokesman said the UN committee's report concluded that Israel had acted within its rights and said he hoped it would help "put the relationship between Jerusalem and Ankara back on the right track."

"The UN commission clearly states that Israel acted legally in imposing the naval blockade to protect our people from the smuggling of rockets and weapons that are fired at our civilians," the spokesman, Mark Regev, said.

The UN report released Friday called the May 31, 2010 Israeli raid "excessive and unreasonable," The UN panel also blamed Turkey and flotilla organizers for contributing to the deaths.

Israel insists its forces acted in self-defence and says there will be no apology. Israeli officials pointed out that the report does not demand an apology. Rather, it says "an appropriate statement of regret should be made by Israel in respect of the incident in light of its consequences."