Four, and possibly five, suspected suicide bombers remained at large last night as the Metropolitan Police in London named two of them.
The race against time was heightened by police fears that they might have access to more explosives and be prepared to strike again.
The political establishment continued to close ranks behind the Met, meanwhile, as an inquest heard that the innocent Brazilian mistaken for a suicide bomber was shot eight times by police at Stockwell tube station last Friday.
Following two further arrests, a total of five men were being questioned in London, as investigators pursued a possible East African connection to Thursday's unsuccessful attempt to bomb three tube trains and a bus.
They are also still exploring possible Pakistani leads to the July 7th bombings which killed 56 people, as well as possible links between some of those involved in both attacks on London's transport network.
Scotland Yard issued fresh images of last Thursday's four original suspects, together with details of their movements, and named two of them as Muktar Said Ibrahim (27) and Yasin Hassan Omar (24).
The possibility of a fifth bomber was raised as deputy assistant Commissioner Peter Clarke confirmed that a device hidden in bushes near Wormwood Scrubs at the weekend was similar to those found at Thursday's crime scenes. This device was also packed into a plastic food container of a type manufactured in India and reportedly sold in some 100 UK outlets.
Mr Clarke appealed to shop owners who may have sold five or more of the containers recently to come forward.
He also appealed to anyone with information about the four suspects' whereabouts to ring 999, while warning: "The public should not approach them."
With pressure on the police mounting and debate about the national "shoot-to-kill in order to protect" policy growing, Prime Minister Tony Blair said he was "desperately sorry" about the death of 27-year-old Brazilian electrician Jean Charles de Menezes and understood the feelings of his family.
But he said: "We also have to understand the police are doing their job in very, very difficult circumstances and it is important that we give them every support." London Mayor Ken Livingstone said Mr Menezes was another "victim of the terrorist attacks".
However the dead man's family are reportedly considering suing the police.
The Independent Police Complaints Commission will investigate key questions, including the nature of any police warning given; why, as has been claimed, Mr Menezes might have ignored it and run away; and why, if he was suspected of being a suicide bomber, he was allowed to board a bus as has been claimed by relatives.
The BBC reported family denials of suggestions attributed to police sources that Mr Menezes had been in the UK on an out-of-date student visa.
The Immigration and Nationality Directorate would not comment on his status until it had studied all the papers