Flowers, notes and appeals for information about missing relatives piled up outside King's Cross station, where bodies were still trapped deep underground. More than 25 people, of many nationalities and religions, were still unaccounted for.

Police said 50 people were confirmed dead in London, but emergency staff were still trying to retrieve bodies in one of the subway system's deepest tunnels two days after the blasts.

So far no victims have been formally identified - and police warn that the process, which began yesterday, could take weeks to complete.

The British government says the attacks bear the hallmarks of Osama bin Laden's Islamic militant al-Qaeda network, which was behind the September 11, 2001 attacks on New York and Washington.

The three bombs on under ground trains "exploded almost simultaneously", say police.

Scotland Yard Deputy Assistant Commissioner Brian Paddick said the attacks took place within 50 seconds of each other.

Technical data from London Underground disproved the earlier wider range of timings between explosions.

British experts have been joined by specialists from Europol to help analyse debris, sort through witness testimony, follow up the thousands of telephone calls made by the public with information and study security camera film.

HOMEMADE DEVICES USED
The British police have said each of the bombs weighed less than 10 pounds and could be carried in a backpack.

An explosives expert said they were likely crude homemade devices set off with a simple timer. Experts say Thursday's attacks had all the hallmarks of an al-Qaeda strike, and authorities were gathering evidence on the ground and investigating a purported claim of responsibility.

Sir Ian Blair, commissioner of London's Metropolitan Police, said no arrests had been made but officials have "lots and lots" of leads.

Home Secretary Charles Clarke, the Cabinet minister responsible for law and order, said it was a "strong possibility" that al-Qaeda or a sympathetic group had carried out the attack.

The bombs were probably made from simple, relatively easy-to-obtain plastic explosives, not the higher-grade military plastics like Semtex that would have killed far more people, said Andy Oppenheimer, a weapons expert who consults for Jane's Information Group.

"Any crook with ready cash could obtain this stuff if they knew where to look for it," said Alex Standish, the editor of Jane's Intelligence Digest.

BACKLASH AGAINST MUSLIMS
The first indications of a possible backlash against British Muslims came Friday with reports of suspicious fires at a mosque in Leeds and a Sikh temple in Kent, as police confirmed that tension around the country was increasing.

Meetings were being held across Britain as the authorities and communities moved to limit any backlash.

Police said about 70 incidents against minorities had been recorded. They ranged from the suspicious fires to two possible assaults, verbal abuse and threatening calls.

Imams used Friday prayers to condemn the bombings and to tell Muslims they "have no reason to feel ashamed" and should go about their daily lives.

The home secretary, Charles Clarke, after meeting faith leaders, including Sir Iqbal Sacranie of the Muslim Council of Britain (MCB), said there were only "very, very minor" indications of a backlash.

He stressed the importance of defending Britain's "multi faith community" and voiced concern about some of the language used in the media, particularly radio phone-ins. "The response should be to ensure that those who try to destroy our multi-faith community should not be able to succeed," he said.

THIRD CLAIM
A group claiming links to al Qaeda called the Abu Hafs al-Masri Brigades said on Saturday it was behind the blasts and suggested it could strike again. It was the third such claim by an Islamist group since the blasts.

"We will not rest until security becomes a reality in the land of Islam and Muslims in Iraq, Afghanistan and Palestine," it said in an Internet statement.

The group has claimed authorship of previous attacks in Turkey and Spain. But intelligence sources have treated its statements sceptically, seeing it as an opportunistic group trying to associate itself to al-Qaeda.

WHO'S NEXT?
After deadly rush-hour bombings in Spain and Britain just over a year apart, Italians and other US allies in Europe are asking themselves: who's next?

Spain blames al-Qaeda for last year's Madrid train bombs and London's police chief has said Thursday's London attacks bore all the hallmarks of the loose Islamist network.

A vocal European proponent of US foreign policy, Italy is a repeated target of Islamic militant threats.

Two different groups claiming affiliation to al-Qaeda have warned of attacks on Italy within the past 24 hours alone.

Italy dispatched extra plain-clothes police to guard public transport, heightened security at airports and said more than 13,000 "sensitive sites" were under special guard. But for many Rome residents, an attack seems inevitable.

"It will happen. Rome is an important city, it's home to the Vatican. Maybe not today, or tomorrow, but eventually," said Rita Pesce, waiting for a bus.

After the United States and Britain, Italy is the third largest Western member of coalition forces in Iraq, and Italian Prime Minister Silvio Berlusconi acknowledged that Italy's role in Iraq left it "exposed" to attack.

Denmark has also sent troops to Iraq and found itself threatened along with Italy by the previously unknown "Secret Group of al Qaeda's Jihad in Europe", which also claimed credit for the London blasts.

Denmark's Foreign Minister Per Stig Moeller said terrorists would inevitably "slip through the net" and warned all European nations were ultimately vulnerable.

Poland, which has about 1,700 troops in Iraq and commands a multinational division, played down the threats.

Even France, which won support in the Muslim world for opposing the Iraq war, is warning that it too could be a target.

French security experts say the risk is high because it shares intelligence with Washington and London, and has helped leaders in its North African ex-colonies fight Islamic radicals. (AFP, REUTERS, The Guardian, AP)

Bangladeshi Shahara a face of London's lost Pretty, London born and bred, and Muslim: 20-year-old Shahara Islam has become the face of London's lost.