Turkey's prime minister says ties between his country and Israel will not improve unless Israel apologizes for the 2010 raid on ships trying to reach the Gaza Strip that resulted in the deaths of nine Turkish activists. The statement came just hours after Israeli officials said Israel's prime minister informed the U.S. he will not tell Turkey that Israel is sorry for the raid.

Turkish Prime Minister Recep Tayyip Erdogan told reporters Wednesday in Istanbul that Turkey would continue demanding an apology.

Earlier, Israeli officials said Prime Minister Benjamin Netanyahu told U.S. Secretary of State Hillary Clinton in a phone call late Tuesday that Israel was standing by its refusal to apologize to Turkey.

The diplomatic stand-off comes days before the United Nations is to publish the findings of its inquiry into Israel's seizure of a Gaza-bound flotilla.

Turkey had long been among Israel's closest friends in the Middle East, but ties were severely strained last year when Israeli commandos raided the aid flotilla as it sailed toward Gaza, killing nine Turkish activists on board the ships.

Israel says its commandos acted in self-defense after an initial boarding party was attacked by activists with clubs and knives. Israel defends its blockade of Gaza, saying it is aimed at stopping arms from reaching Hamas, an Islamist militant party that controls the area.