Israel began deporting all the foreign activists detained during a deadly raid on a Gaza-bound aid flotilla, as international pressure mounted for a full investigation of the incident.

The Jerusalem Post reports,

Israel on Tuesday night rejected international calls to end its naval blockade of Gaza and to launch an “independent” investigation into the death of at least nine activists during an IDF raid of the Mavi Marmara passenger ship, which was part of a flotilla that aimed to break that closure.

“It’s important to understand that this [blockade] is essential to protect Israel’s security and its right to defend itself,” Prime Minister Binyamin Netanyahu told a special meeting of the diplomatic-security cabinet in Jerusalem.

Gaza is an “Iranian-sponsored terrorist state,” and as such it is vitally important to prevent the entry of weapons there, whether by air, sea and land, he said.

Pro-Palestinian activists behind the aid convoy meanwhile vowed to renew their bid to break the Israeli blockade and deliver their cargoes to the Palestinian territory in the coming days.

"All foreign nationals who were on board the fleet and were arrested will be deported from Tuesday night," said a statement from the office of Israeli Prime Minister Benjamin Netanyahu.

The operation was expected to be completed within 48 hours, it added.

Early Wednesday, an Israeli government official told AFP that a first group of around 50 Turkish nationals were headed to Ben Gurion airport near Tel Aviv, from where they would be deported.

The decision to release the activists came after mounting international pressure to free the detainees.

The UN Security Council called for the ships and the civilians who had been on board to be released and to transport the aid to Gaza.

It also called for "a prompt, impartial, credible and transparent investigation conforming to international standards."

Israeli troops said they had killed nine of the activists during Monday's operation to capture the six-ship flotilla, which had 682 passengers from 42 countries.

Pierre Wettach, head of the International Committee of the Red Cross delegation, said his group was checking on the condition and whereabouts of those wounded and those detained by Israeli authorities.

Israel's decision to back down and release the detainees followed two days of stinging international criticism.

It was all the more remarkable given that just hours earlier, Netanyahu had described some of the activists as "terrorists armed with cold weapons such as axes, knives, clubs, bars and the like."

The White House declined to specifically condemn Israel, but US Secretary of State Hillary Clinton said the situation in Gaza was "unsustainable and unacceptable."

"Israel's legitimate security needs must be met just as the Palestinians' legitimate needs for sustained humanitarian assistance and regular access for reconstruction materials must also be ensured," she added.

Clinton backed an Israeli probe of the raid, while stressing that it had to be "prompt, impartial, credible and transparent."

Israel insists the boarding would have been peaceful if the commandos had not been attacked by dozens of club-wielding activists on the Turkish ferry Mavi Marmara, which carried most of the passengers.

Organisers of the aid convoy meanwhile insisted they would push ahead with a fresh bid to break the blockade.

"We knew what the risk would be and we will continue to run these flotillas," said Greta Berlin of the Free Gaza Movement.

"The Rachel Corrie will probably be there within the week."

The aid-laden cargo ship, currently off the east coast of Italy, is named after a US activist crushed to death in 2003 by an Israeli army bulldozer during a protest on the Gaza Strip.

Greta Berlin said organisers were also working on plans for a new flotilla that would leave for Gaza in July.

But Israel was adamant it would not let any ships through.

"We will not let any ships reach Gaza and supply what has become a terrorist base threatening the heart of Israel," deputy defence minister Matan Vilnai told public radio.

Turkish Prime Minister Recep Tayyip Erdogan called for Israel to be punished for its "bloody massacre" and urged international sanctions against its "lawlessness."

Israel has informed Turkey that at least four of the nine passengers killed were Turkish nationals, a Turkish diplomat said.

And while Israel blamed the activists for the confrontation, passengers had an entirely different story.

"Personally, I saw two and a half wooden batons that were used... There was really nothing else. We never saw any knives," former MP Norman Paech, 72, said on his arrival back in Berlin.

"This was a clear act of piracy," said Paech, who was on the Mavi Marmara, where the worst of the violence took place.

Netanyahu, who consulted with his security cabinet after calling off White House talks with US President Barack Obama, insisted the commandos had "defended themselves from a lynching."

But the Israeli press was scathing about the botched operation, criticising the failure of the political and military leadership to anticipate such a scenario.

Flotilla organisers said the ships carried some 10,000 tonnes of aid destined for Gaza, which has suffered a crippling blockade imposed by Israel in 2006 and largely backed by Egypt.

Israeli authorities said some of the fleet's supplies had been trucked to Gaza and more would follow.

The political fallout from the incident continued late Tuesday, as Nicaragua suspended diplomatic relations with Israel.

(with additional reporting by RAW STORY)