POLICE are hunting four would-be suicide bombers who tried and failed to launch a second wave of terror attacks in London.

The men who targeted three Tube trains and a bus two weeks after the 7/7 bombings appear to have escaped from their targets.

Now a massive manhunt is underway to track down the men.

Capturing the men would provide police with an opportunity to infiltrate the network of terror that led to the strikes.

In a coordinated strike eerily similar to events a fortnight ago Tube trains and a double-decker bus bound for Hackney Wick were targeted.

Two people arrested yesterday, one in Whitehall close to Downing Street and a second man near Tottenham Court Road, were released without charge by police earlier today.

Scotland Yard said they were unable to confirm eyewitness reports from the University College Hospital that said a man had been detained by armed police inside the building.

It is thought one of the would-be bombers escaped the clutches of police and passers by after a chase outside Oval Tube station in south London.

Police are now appealing for witnesses at the Oval in Brixton Road, Warren Street, Shepherd's Bush, Kensington and Hackney to come forward.

Officers will be at these locations today to take witness statements.

Police are also appealing to anyone who may have photos or mobile phone images from any of the incident scenes, either at the time of the incident or shortly before, to send them online via www.police.uk.

Information can also be submitted to police through the same website, or alternatively through the confidential anti-terrorist hotline on 0800 789321.