Jerusalem - Israel struck a defiant tone Tuesday over its lethal raid of a Gaza-bound humanitarian flotilla, saying it had nothing to apologize for even as much of the world called for an end to its three-year blockade of the coastal Palestinian enclave.

Israel's hard-line response came as organizers of the flotilla said they were sending another ship to attempt to break the long-standing siege, which began after the militant Palestinian group Hamas took control of Gaza in 2007.

The border restrictions were partly lanced Tuesday when Egypt, facing diplomatic pressure from fellow Muslim nations, announced it would open its own crossing into the Gaza Strip at Rafah to allow shipments of humanitarian and medical supplies.

Meanwhile, activists released by Israel began issuing their eyewitness accounts of the confrontation at sea. The initial firsthand versions had come almost exclusively from the Israeli government, which jammed communication with the flotilla and incarcerated most of the activists once ashore. Israel's military released video it said showed its commandos being attacked on board the Mavi Marmara, a Turkish ship leading a Turkish-sponsored convoy, by activists armed with sticks and other weapons. It said its commandos fired live rounds only in self-defense.

On Tuesday, the captain of one of the other ships in the flotilla, Capt. Huseyin Tokalak, said Israeli ships opened fire on the Mavi Marmara before boarding that ship, according to Reuters. He also said Israel had threatened to sink his ship unless commandos were allowed to board and take control. "They started shooting directly at Mavi Marmara. They didn't care if it was the front or back of the ship," Tokalak said.

The emergence of contrasting versions of the melee at sea fueled calls for an independent international inquiry. The White House appeared sympathetic to some form of inquiry, issuing a statement Tuesday saying that President Barack Obama offered U.S. support for "a credible, impartial and transparent investigation of the facts," during a condolence call to Turkish Prime Minister Recep Tayyip Erdogan.

Israeli government officials have not indicated whether they intend to open a formal inquiry. Prime Minister Benjamin Netanyahu, who returned hastily to Israel from Canada after canceling Tuesday's planned White House meeting with Obama, made only brief statements, defending the raid and saying his administration has no plans to alter its policy toward Gaza.

"We have a simple policy, which will continue," the prime minister said.

Israel says a continuing siege is needed to prevent Hamas from receiving weapons and foreign support from Iran and other anti-Israel countries. In recent months, Israel has allowed trucks to cross into Gaza with limited amounts of clothing and cement; many food items and essential goods are available but many families cannot afford to pay for them.

Deputy Foreign Minister Danny Ayalon scoffed at calls for Israel to apologize, saying flotilla activists prompted the violence by attacking soldiers during the raid. "We do not need to apologize for defending ourselves," he said.

But Israel did say it would release - and deport - the 680 activists it had arrested. And as international criticism of the raid swelled, the public mood appeared to shift in Israel as well, with many questioning whether the botched predawn raid on a ship in international waters was worth the damage to the country's image.

Israeli newspaper headlines Tuesday used language like "fiasco" and "flawed policy" to describe what they saw as a poorly planned mission and clumsy handling of the political aftermath, with some calling upon Defense Minister Ehud Barak to resign.

And some voices inside Israel were raised against continuing the cordon around Gaza. Imposed in response to the Hamas takeover of Gaza and the kidnapping of Israeli soldier Gilad Shalit, who is still being held in Gaza, the naval blockade and border restrictions have failed to bring about Shalit's release or to help force Hamas from power.

Meanwhile 1.5 million Gazans struggle to survive on a limited amount of aid parsed through Israeli screening and whatever can be smuggled in through a network of tunnels. A policy that was initially aimed at isolating Hamas has instead largely isolated Israel, many analysts say, noting that the country has been frequently criticized by the U.N., U.S., European Union and numerous countries for preventing enough food and medical supplies from reaching Gaza.

"We are no longer defending Israel," wrote columnist Bradley Burston in Haaretz, a leading Israeli newspaper. "We are now defending the siege. The siege itself is becoming Israel's Vietnam."

The sharpest breach in Israel's alliances appeared to be with Turkey, one of its few friends in the Muslim world but with which it has seen deteriorating relations since its incursion into Gaza in 2009. Monday's deaths at sea occurred aboard the Mavi Marmara. At least four of the nine dead activists were believed to be Turkish citizens.

On Tuesday, Turkish Prime Minister Erdogan called the raid a "bloody massacre," and told the country's parliament that "nothing will be the same again."

Erdogan's support for the pro-Palestinian flotilla contributed to his rising reputation among Israel's critics in the Middle East, many of whom have become disillusioned with the ability of longstanding regional leaders such as Egypt's President Hosni Mubarak to improve conditions for the Palestinians.

Turkish anger was also apparent in Washington, where its foreign minister, Ahmet Davutoglu, complained that the Obama administration had watered down a Security Council statement negotiated Monday night in New York. The 15-member Council issued a carefully crafted condemnation, which criticized "acts" of violence, but did not specifically condemn Israel.

Turkey and others lobbied for stronger language, including demands for an international probe into the raid, but accepted the vaguer language in order to secure U.S. support.

"We expect full solidarity with us," Davutoglu said. "It should not be a choice between Turkey and Israel. It should be a choice between right and wrong."

But Israel rejected the Security Council statement. Foreign Minister Avigdor Lieberman telephoned U.N. Secretary General Ban Ki-moon to complain about what he called the international community's "hypocrisy and double standards" in dealing with Israel and calling the U.N. statement "unacceptable."