Passengers on a Tube train in south London desperately tried to catch a man who fled after his rucksack exploded in a carriage, witnesses said.
A woman on the train at Oval station on the Northern line described seeing a man dash off the train at about 12.30pm, leaving the bag behind. Others said a man waiting at the station dumped the bag in a carriage and fled back up the escalator.
The female passenger told Sky News: "There was a little explosion. As soon as the door opened, the man ran away and people were trying to run after him. There were three men struggling with him but he ran off and they couldn't catch him."
Another witness said: "There was a popping, it sounded like champagne popping. Then I heard shouting from the next-door carriage. People started saying, 'Smoke, smoke'.
"One of the train guys came through and said 'We're evacuating, everyone out'.
"As we were walking past the carriage, we could see the bag sitting on the chair. It was a big, black rucksack."
A woman passenger said: "A policeman on his way to work... got us all off the train.''
Those in the ticket hall upstairs said they saw a young man of Asian appearance aged about 18 run through the station, pursued by others. Several passers-by also gave chase with one trying to rugby tackle the man.
Hugo Caillat, 25, a DJ from France who lives near by, said he was inside the station buying a ticket. "I heard people shouting and then this young Asian came running past. He was looking around to see if anyone was behind him. He looked really confused. He was shouting: 'What's wrong with these people?'."
Paul Martin, from London, arrived at the station as chaos broke out. "People started running out and I saw a guy being chased. It was completely crazy.
"People were trying to drop him, to rugby tackle him. There was a general mêlée."
Police kept a wide cordon around The Oval all afternoon as bomb disposal officers visited the station several times.Dozens of potential witnesses were being questioned at a police station yards from the Oval station last night.
Police shut a half-mile stretch of Kennington Park Road and Clapham Road, one of the busiest arteries in south London.
Leticia Frank, 24, from Brazil, who lives near Oval station, said: "I was not scared after 7 July, but from now on I will be more worried. This is so random."
Many local residents were spending the evening sitting on the edge of police cordons around Oval Station unable to return to their homes.
Four officers wearing white boiler suits and royal blue gloves were seen conducting a detailed search of gardens and bins along Clapham Road.
A police officer in fluorescent clothing who was standing outside the four-storey terraced property confirmed that the activity was related to the Oval Tube incident. "Some clothing has been found," he said.