The expulsion of activists - including more than 40 Britons - detained during the storming of an aid flotilla heading for the Gaza Strip is under way.
All the 679 detainees taken off the ships during the Israeli military-led action which saw nine civilians killed will be deported within 48 hours, but about 50 will be held for questioning, a statement from the Israeli government said.
Earlier, Foreign Secretary William Hague said 31 British nationals and a further 11 with dual nationality were known to have been detained after the seizure of the vessels as they attempted to breach the Israeli blockade of the territory.
One Briton who was on one of the ships heading towards Gaza arrived back in Britain on Tuesday night. IT professional Hasan Nowarah, from Glasgow, described the moment the aid flotilla was stormed by Israeli troops.
He told Sky News the Mavi Marmara ship was surrounded by helicopters and a Zodiac assault craft. He said the attack happened "out of the blue". "All I could hear was screaming and bullets all over the place, over the Marmara, the Turkish ship. All you could see was screaming and bullets. Out of the blue as I looked around our ship, all I could see were hundreds of Zodiacs. Hundreds of Zodiacs full of soldiers, and big ships, lots of ships, and I believe as well submarines in the sea."
Following a meeting of Israel's security and diplomatic cabinet, the statement said last night: "It was agreed that the detainees would be expelled immediately - according to the procedures set by law. "The interior minister announced that the expulsion will begin this evening, and the assessment is that it can be completed in approximately 48 hours."
The Israeli authorities said 50 of the 679 activists taken off the flotilla had already been taken to Israel's international airport for deportation. The rest were being held at the Be'er Sheva detention centre in southern Israel, having refused to identify themselves.
However there was anger and concern among friends and relatives in the UK who complained that they were unable to establish contact with the detainees or find out what was happening to them.
Rachel Bridgeland, whose partner, Peter Venner, 63, from Ryde, Isle of Wight, was on the Turkish aid ship the Mavi Marmara, said that the Government should be putting more pressure on Israel. "It's absolutely terrible not knowing what has happened to him and it's terrible that the British Government hasn't done more, but they don't want to fall out with Israel," she said. "They should insist that the British people are allowed to phone us, they have done nothing illegal."
The British detainees were also thought to include Sarah Colborne, campaign and operations director for the Palestine Solidarity Campaign (PSC).