Metropolitan police have released CCTV images of four men they are urgently trying to trace in connection with yesterday's failed bomb attacks in London.
They urged anyone who may know the men not to approach them but to contact police immediately.
One image shows a man running from Oval tube station. The distinctive 'New York' top he is seen wearing was later found discarded in Brixton.
The other images show another suspect on the top deck of the bus on which a rucksack bomb was left and two men leaving two other stations after their rucksack bombs failed to explode.
Meanwhile, police investigating yesterday's attacks have arrested a man in Stockwell in the south of the city.
The arrest comes after police shot dead a man in Stockwell Underground Station earlier today.
Eyewitnesses said an Asian man was pursued by three armed plainclothes officers into Stockwell tube station. He leapt over a barrier and was chased onto a train.
According to one eyewitness on the train two plainclothes officers pushed the man to the floor while a third officer shot the man five times with a semi-automatic pistol.
Stockwell Tube Station was evacuated and Victoria and Northern Lines services, which pass through it, were suspended.
House search in attempted attacks probe
In another development, Scotland Yard has confirmed that detectives investigating yesterday's attempted bombings searched an address in the Harrow Road area of West Kilburn.
Armed police were reported to have told residents around Harrow Road to stay off the streets. One witness told the BBC News that he saw remote controlled trucks that he thought were used by bomb disposal units.
Earlier, armed police surrounded a mosque in east London following a telephone threat saying a bomb had been left there.
Forensic experts examine explosives
Three of the four devices found yesterday are thought to be of similar size and weight to the bombs used in the 7 July attacks in which 56 people were killed.
The fourth was smaller and appears to have been contained in a small plastic box.
In the case of three of the devices, it appears the detonators went off but that the bombs failed to explode.
Forensic experts are now trying to establish if the explosive is linked to that found in a house in Leeds following the blasts in London two weeks ago.
As on 7 July, the attacks were almost simultaneous and were carried out at three underground stations and on a bus.
Concern has again being expressed about the quality of intelligence on terrorist activities in Britain.
However a former Chairman of the UK's Joint Intelligence Committee, Dame Pauline Neville-Jones, said tracking down terrorists was something that took time.
- News At One: Brian O'Connell, London Editor, reports from Stockwell Station on what is known so far about today's shooting
- News At One: Mark Whitby, an eyewitness who was on the underground just yards from the man shot by police, describes what he saw
- Morning Ireland: Simon Lubin, spokesperson for British Transport Police, says that the London transport system is getting back to normal this morning
- Morning Ireland: Boris Johnson, Conservative MP for Henley-on-Thames, discusses the situation and fall out for the Muslim community following the latest copy-cat terror attack
- Morning Ireland: Séan Whelan, Europe Editor, discusses the atmosphere in London after the failed terror attack
- Nine News: Seán Whelan speaks about the tense mood in London
- Nine News: Random searches are introduced on the New York subway
- Nine News: Brian O'Connell discusses the security operations in the Stockwell area of the British capital
- Nine News: Seán Whelan, Europe Editor, reports on the security alerts that have caused a series of transport disruptions and suspensions in London
- Nine News: Brian O'Connell, London Editor, reports as CCTV images of suspected suicide bombers are issued by police
- Six One News: Bryan Dobson has news that a man has been arrested at Stockwell Station in south London
- Six One News: Andrew Silke, counter terrorism expert at the University of East London, analyses what motivation was behind yesterday's failed attacks
- Six One News: Brian O'Connell reports live from London with more detail on the manhunt underway for the four men suspected of involvement in yesterday's failed attacks
- Six One News: Seán Whelan, Europe Editor, reports on ordinary Londoners' views of life in the city amid further security alerts and bomb scares
- Six One News: Brian O'Connell, London Editor, reports on today's events in London as police investigate the 7 July attacks and yesterday's failed bombings
- One News: Seán Whelan describes the mood amongst commuters in London
- One News: Brian O'Connell, London Editor, reports live from Stockwell Tube Station
- One News: Seán Whelan, Europe Editor, explains that the man shot dead was a suspected bomber
- News At One: Dr Andrew Silke, terrorism expert at the University of East London, analyses the possible implications of yesterday's incidents
- Morning Ireland: Peter Neumann, a research fellow in international terrorism at Kings College London, discusses the fact that the bombers were born and bred in the UK
- Morning Ireland: Séan Whelan gauges the mood this morning amongst London commuters
- Morning Ireland: Brian O'Connell, London Editor, describes the pervading mood in London
