The bungled operation on an aid flotilla bound for Palestinians in Gaza brought an international chorus of outrage and intensified calls for Israel to end its vice-like siege.

Even Israel's staunchest ally, the US, has declared the blockade "unsustainable and unacceptable," while aid groups say it is causing a humanitarian crisis in Gaza.

British Prime Minister David Cameron took a tough stand against Monday's raid, terming it "completely unacceptable."

In his first public comments on the situation, Cameron said he had also spoken to Turkish Prime Minister Recep Tayyip Erdogan "to extend our condolences for the Turkish citizens who have been lost". "What has happened is completely unacceptable, we should be clear about that and we should also deplore the loss of life," Cameron told lawmakers.

"We should do everything we can to make sure this doesn't happen again and I stressed this point in a conversation with Prime Minister Netanyahu of Israel," he added.

Middle East envoy Tony Blair also called on Israel to end its embargo on Gaza Strip, saying it was “counter-productive”.

Britain and the United States have discussed what can be done to ease the Israeli blockade on Gaza, Foreign Secretary William Hague said on Wednesday.

Hague told Parliament that the incident “from the unacceptable and unsustainable situation in Gaza.” “We will ... continue to press the Israeli government to lift the closure of Gaza, and plan early discussions with Israel as well as our other international partners about what more can be done to ensure an unfettered flow of aid while ensuring that aid reaches those who need it and is not abused,” he said.

“I discussed this with (US) Secretary (of State Hillary) Clinton last night and we will be taking forward discussions on this subject urgently,” said Hague, a senior member of Britain’s new Conservative-Liberal Democrat coalition.

Meanwhile, Israel on Wednesday began deporting the bulk of nearly 700 international activists detained during the outrageous raid. The hundreds of activists detained on the boats and taken to Israel have all been released for deportation, Israeli prisons authority spokesman Yron Zamir said. They were all taken to Tel Aviv airport or the Jordanian border.

Several of the activists deported to Jordan said that they were deprived of food, water, sleep and access to toilets in Israeli detention.

"The Israelis roughed up and humiliated all of us — women, men and children," said Kuwaiti lawmaker Walid Al-Tabtabai, who was on board one of the ships with other activists from Muslim countries. "They were brutal and arrogant, but our message reached every corner of the world that the blockade on Gaza is unfair and should be lifted immediately," he added. The lawmaker claimed there "was not a single weapon with the passengers aboard all the ships."

Saudi Minister of State for Foreign Affairs Nizar Madani led the Saudi delegation to the emergency meeting of the Arab Foreign Ministers held in Cairo on Wednesday to discuss the situation, according to Saudi Press Agency.

Meanwhile, the Turkish Parliament urged the government to implement "effective" measures against Israel over the raid. Parliament "expects the Turkish government to review our political, military and economic ties with Israel and take necessary effective measures," read a declaration adopted unanimously in the general assembly. "Turkey should resort to national and international legal means against Israel," it added.

In a separate development, Palestinian President Mahmoud Abbas said on Wednesday he would ask US President Barack Obama to take "bold decisions" on Middle East peace during an upcoming visit.

"My message to Obama during our meeting in Washington next week will be that we need bold decisions to change the face of the region," Abbas said at the opening of a Palestinian investment conference in the West Bank.

"My message to all parties is that we need bold decisions to change the face of the region and end the suffering and the pain and the Israeli occupation of Palestinian lands," Abbas said. Abbas accused Israel of "state terrorism" over the violent seizure of the ships.

"The Palestinian people were facing state terrorism when Israel attacked the Freedom Flotilla. The Palestinian people and the entire world are confronted with this terrorism," he said. "We ask the world, how long will this go on? It's a big question. When will this tyranny and occupation end, and when will Israel respect the freedom of the Palestinian people?"

In the meantime, investors and donor countries have pledged nearly $1 billion worth of programs at the start of the two-day West Bank investment conference. The conference is part of the international community’s attempt to revive the West Bank economy and make the Palestinians less dependent on foreign aid.

Meanwhile, Irish Prime Minister Brian Cowen is appealing to Israel to let a private Irish ship deliver its aid cargo to Gaza — but concedes that supplies of concrete on board pose a stumbling block for the Israelis.

The 1,200-ton ship Rachel Corrie is waiting off the Libyan coast and carries both medical equipment and concrete. Cowen said Ireland has put in a formal request to Israel to let the ship "complete its journey unimpeded and discharge its humanitarian cargo in Gaza." But he admitted that Israel does not consider cement a humanitarian product.