11:09pm UK, Friday July 22, 2005

Police have issued CCTV pictures of four men they urgently want to speak to in connection with the attempted bombing in London this week.

180 police outside stockwell tube shooting

Scene under guard

The pictures were taken at Tube stations and on a bus where small explosions occured on Thursday.

Assistant Police Commissioner Andy Hayman said the men should not be approached by the public, and that anyone with any information should phone 999 immediately.

He said: "These are four men we urgently want to trace in connection with attempts to detonate four explosive devices on the transport system in central London.

"It's crucial that detectives are able to question them about events at the Oval, Shepherd's Bush and Warren Street London Underground stations and a route 26 bus in Hackney Road."

The pictures show one man running away from a Tube station, two other men caught on film at two other stations, and one on the top deck of a bus.

Scotland Yard said a man has been arrested in Stockwell in connection with the investigation, following a raid on a block of flats.

The arrest came after police killed a suspected suicide bomber at a Stockwell Tube station in south London.

The man, who was shot dead  is not thought to be one of the four shown in the CCTV pictures.

At Stockwell Station, armed officers opened fire on the suspect after he hurdled a ticket barrier and raced along a platform.

Police screamed at passengers to evacuate and are thought to have shot the suspect as he stumbled on to a train.

Alarmed onlookers said they saw up to 10 plain-clothed officers chasing an Asian-looking man before opening fire.

Metropolitan Police chief Sir Ian Blair said the shooting was "directly linked" to ongoing anti-terrorist invetigations in the capital.

He said the man had failed to comply with instructions from police before he was shot dead. 

The public should not approach these men and should dial 999 immediately if they know of their whereabouts, a spokesman said.

Witness Mark Whitby was on the train as he saw a big man wearing a large coat and "looking absolutely petrified" lurch through the doors.

Admitting to being "totally distraught", he went on: "He half-tripped, was half-pushed to the floor.

"The policeman nearest to me had the black automatic pistol in his left hand, he held it down to the guy and unloaded five shots into him."

A Scotland Yard spokesman said: "We can confirm that just after 10am armed officers shot a male at Stockwell Underground station.

"A man was challenged by officers and subsequently shot. London Ambulance Service attended the scene. He was pronounced dead at the scene."

Police are believed to be under orders to shoot to kill if they believe someone is about to detonate a bomb.

Sky News Crime Correspondent Martin Brunt said: "The officer or officers involved in this clearly felt this suspect was about to detonate a bomb."

Three eyewitnesses were taken to a nearby veterinary surgery by police before being taken away for interview.

Armed police also raided a house in north-west London thought to be linked to one of four men being hunted in connection with the failed bombings in the capital.

Witnesses described how officers descended on an area surrounding Harrow Road, in West Kilburn, cordoning off streets and shouting at residents to stay indoors.