JERUSALEM (AP) ― Israel’s leader defiantly refused on Sunday to apologize to Turkey for a deadly Israeli raid on a Turkish-led flotilla bent on breaching Israel’s Gaza Strip blockade ― an incident that has battered a relationship once seen as a cornerstone of regional stability.

In his first public remarks since Turkey announced Friday that it would expel the Israeli ambassador over the affair, Benjamin Netanyahu expressed Israel’s regret for the loss of lives in the May 2010 raid and said he hoped to mend ties with Turkey, formerly Israel’s closest ally in a Muslim world largely hostile to its existence.

Ankara had wanted Israel to apologize for the deaths and lift the embargo on Gaza, a Palestinian territory run by Hamas militants with a long history of deadly violence against Israel.

Netanyahu said Israel, in trying to keep arms from reaching Gaza, had nothing to apologize for. “We need not apologize for acting to defend our civilians, our children and our communities,” Netanyahu told his Cabinet and journalists.

He said Israel “expressed regret” over the deaths ― a formula Turkey had already deemed to be an unacceptable substitute for an apology ― and voiced hope the two countries would shore up their frayed ties.

“Israel never wanted ties with Turkey to deteriorate, and Israel does not now seek a deterioration of ties,” Netanyahu said.

The decision to expel the Israeli envoy from Turkey on Friday followed the leaking of a U.N. report on the bloodshed. The report, accepted by Israel and rejected by Turkey, defended the embargo on Gaza and said violent activists on board the blockade-busting Mavi Marmara had attacked the raiding naval commandos.

But it also accused Israel of using disproportionate force against the activists and called the deaths of eight Turks and one Turkish-American “unreasonable.”

Israel blockaded Gaza in 2007 in cooperation with Egypt after the Islamic Hamas violently overran the territory. The declared aim was to keep militants from bringing weapons into the enclave and to weaken Hamas. But the blockade did not achieve its aims, while it did deepen the destitution of Gaza’s 1.6 million people and confine them to their tiny seaside territory.

The bloodshed on the Mavi Marmara sent already brittle Israeli-Turkey relations sinking to a new low.

The sides worked to find a formula that would appease the Turkish demand for an apology, but those attempts failed.

Asked if new Turkish conditions, such as the lifting of the since-eased blockade, made reaching an accord difficult, Israeli Foreign Ministry spokesman Yigal Palmor said the Turks “upped the ante every time.”

“First it was an apology and compensation. Then they wanted to shelve the (U.N.) report once they saw the draft. Then they wanted to lift the blockade on Gaza as a condition. There was no end to that,” Palmor said.

Israel’s good ties with Muslim Turkey had been a boon for Israel. Both sides benefited from Ankara’s strong defense alliance with Israel’s powerful, high-tech military.

Ankara also mediated several rounds of indirect and ultimately unsuccessful negotiations between Israel and Syria in 2008.

But relations began to suffer after the Islamist-oriented Recep Tayyip Erdogan became Turkish prime minister in 2003. Erdogan has embarked on a campaign to make Turkey the regional heavyweight, at once pulling closer to Iran ― Israel’s most potent enemy ― while competing with Iran in an attempt to become the leading voice in the Muslim world. This shift away from the Western camp has steadily put Ankara at odds with the Jewish state.

Frictions exploded after Erdogan attacked Israel repeatedly for the deaths of Palestinian civilians in Israel’s war in Gaza nearly three years ago, at one point storming off a stage he shared with the Israeli president at a high-profile world economic forum.

Once-flourishing tourism from Israel to Turkey immediately fell off, and Turkey canceled joint military exercises with Israel.

Turkey’s near-rupture of ties increases Israel’s isolation at a delicate time. Israel worries that Turkey’s alienation will become a model for Egypt, where calls to revoke the 32-year-old treaty with the Jewish state have multiplied since the ouster of longtime leader Hosni Mubarak.

It also comes as Israel seeks to muster international support against the Palestinians’ attempt to have a state recognized at the U.N. this month. The uprising in Syria, which shares borders with Israel and Turkey, adds new uncertainty to the regional mix.