Protesters condemn Israel for attack on aid flotilla

The ships, carrying about 10,000 tonnes of aid and up to 700 passengers – eight of them Irish citizens and 28 reportedly British – on six vessels, were warned not to pass an Israeli sea blockade in the early hours of yesterday.

As part of a series of lightning protests in Britain, hundreds of activists blocked Whitehall shouting "Free Palestine" and carrying

flags and banners with slogans such as "Stop Israel's War Crimes in Gaza" and "End the Criminal Siege of Gaza".

In Yorkshire, people from all over the region joined a banner-waving assembly which attracted more than 150 people to the St Sampson's Square and Parliament Street area of York.

Mr Hague said the British embassy was in "urgent contact" with the Israeli government, asking for more information amid fears that the casualties included British nationals.

The White House said in a written statement that the US "deeply regrets" the loss of life and injuries and was working to understand the circumstances surrounding this "tragedy".

Nothing has been heard since the violence of two members of the Palestine Solidarity Campaign (PSC), who travelled from Bristol to join the flotilla – Sakir Yildirim, from Fishponds, and Cliff Hanley, from Southville.

Richmond MP Mr Hague called for a "full and impartial and independent" probe of the deadly assault.

He said: "We will all want to know more about whether more could have been done to minimise the risks or to reduce the number of deaths and injuries.

"That is why we agree with our EU partners and other international partners that there must be a full and impartial and independent investigation or inquiry into these events."

The Foreign Secretary said the UK remained "in urgent touch with the Israeli government both in Israel and in London, seeking more information about UK nationals who have been involved".

"Of course, Israel must provide consular access to those individuals as that information becomes available," he said.

Israeli Prime Minister Benjamin Netanyahu, who cancelled planned talks at the White House with Barack Obama today, voiced regret at the loss of life but said his soldiers were attacked and "had to defend themselves".

He also vowed to maintain the blockade of Gaza – insisting Israel's concern was to prevent arms being smuggled in, not to stop aid.

Leading QC Michael Mansfield said it was owing to a "chance decision" that he was not on the flotilla himself. "I am incensed, I am volcanic about the actions of the Israeli government," he said.

The leader of the centre-right European People's Party in the European Parliament, Joseph Daul, said: "We are shocked with the Israeli military operation that resulted in the loss of so many lives. Many questions have to be answered."

Martin Schulz, leader of the Socialist Group in the European Parliament, said: "The use of lethal force against civilians on these ships is unacceptable. Israel has crossed a line."

The York protest attracted students, children and older people with the oldest aged 90. They waved banners and flags and addressed the bank holiday crowds over a loud hailer.

Organiser Heather Stroud, 60, from York, of York Palestinian Solidarity Campaign, said: "We are demonstrating to show Israel is not above the law and is accountable for war crimes. If anyone else attacked a boat in international waters they would be pirates. But they spin it that they are the victims and they are not."

The convoy was to highlight the Israeli blockade of Gaza imposed three years ago.