Turkey barred an Israeli military plane from using its airspace after last month's raid on Gaza-bound aid ships killed nine activists, the country's prime minister said on Monday, as Turkish media reported a second plane was also turned away.
The new sign of heightened tensions between the former close allies was revealed as Israel started an official inquiry into the raid in which Israeli commandos shot dead eight Turks and a dual US-Turkish citizen.
"They (Israel) requested an overflight permission to Poland in the first days after the May 31 raid on the aid ships," Erdogan told reporters on his return from the G20 summit in Canada. "They were denied permission."
Erdogan refused to elaborate how Turkey would respond to similar requests by Israel in the future.
The Anatolia news agency quoted the prime minister as telling reporters in Toronto after the summit that his country had closed its airspace to Israel.
A Turkish diplomat confirmed to AFP that one Israeli military flight had been banned and said that future requests would be evaluated on a case-by-case basis.
"Military planes are required to obtain overflight permission before each flight," the diplomat said on condition of anonymity.
"One military plane was denied permission immediately after the raid due to the conditions of the day," he added, stressing that civilian flights remained unaffected.
Israeli daily Yediot Aharonot said the military plane had been taking an army delegation of 100 officers to the former Nazi death camp of Auschwitz in Poland, Turkish media reported.
The Boeing 707 had to take an alternative route, the report said.
Late Monday on its website, the Hurriyet Daily News, citing diplomatic sources, reported that Turkey rejected "two different Israeli requests to use Turkish airspace since the beginning of June".
It was not immediately possible to confirm the second flight ban.
"Even a partial closing of Turkish airspace constitutes an important sign of the deterioration of relations in all areas, including military ties," the newspaper said.
Meanwhile, Israel's Transport Minister Yisrael Katz said Monday the country had not been informed of any procedural changes for entering Turkish airspace, the statement said.
It did not mention reports Turkey had tightened rules on Israeli military overflights but officials said they were unaware of any change in basic procedures, which require flight plans to be submitted ahead of time in every case.
Ankara recalled its ambassador to Israel immediately after the raid on the Gaza-bound ship, scrapped plans for three joint military exercises and said economic and defence links would be reduced to a "minimum level".
Senior officials have said that Turkey expects Israel to apologise for the deaths and injuries, compensate the victims' families, agree to an international inquiry and release three Turkish vessels seized in the operation.
Ankara also wants the crippling blockade of the Gaza Strip to be lifted.
Erdogan said ties with Israel would recover if the Jewish state met the demands.
"We have been very patient ... and have said that meeting our demands would be an important step to turn this process into a positive one. But if they are not met, then we should not forget that our friendship has already been weakened," Anatolia quoted him as saying.
If Israel fails to meet the demands, Turkey will downgrade its diplomatic representation to the level of a charge d'affaires, a senior diplomat told AFP on condition of anonymity earlier this month.
Ankara would consider making no new cooperation agreements with Israel, the diplomat said, adding that existing deals were being reviewed.
Israel says its soldiers acted in self-defence after they came under attack from the activists during the raid and has set up its commission with two foreign observers to investigate the operation.
Israeli Prime Minister Benjamin Netanyahu will be the first witness to testify before the committee set up by Israel which began deliberations on Monday, a spokesman said.
Defence Minister Ehud Barak and Chief of Staff Gabi Ashkenazi would also appear before the commission, with all the major testimony likely some time after Netanyahu holds talks with US President Barack Obama in Washington on July 6.
Israel and Turkey built a strong alliance after a 1996 military cooperation deal, but the relationship has nosedived amid sharp criticism from Ankara over the Jewish state's war on Gaza in late 2008 and early 2009.