AT least two people, a man and woman, are reported to be critically injured after last night's bomb.
Two police officers were among a further four people who were seriously hurt. Scotland Yard said "there were 100 "walking wounded" after the bomb blast in east London including a five year-old girl with facial injuries. But there were no reports of fatalities.
Sixteen injured people were taken for treatment to the Royal London Hospital, the London Ambulance Service said. Paramedics treated others injured at the scene.
Eyewitnesses described how injured people walked from the scene with blood streaming from facial cuts.
Mr Terry Walker, who works for a magazine based in a nearby office block, said: "The whole of the front of the three South Quay buildings are out and the station is wrecked. A building diagonally across the road is badly damaged."
Mr James Brucher, an American engineer who works in an office block next door to the bombed buildings, said: "We were working at our computers when the blast went off. Everything rocked. The blast lifted me from my chair and the ceiling literally rocked."
Scotland Yard said the blast happened in the underground car-park of a six-storey office block at South Quay, Marsh Wall. A spokeswoman said the building partially collapsed and there was extensive damage to surrounding buildings. A gas main on a neighbouring street fractured, she added.
A Scotland Yard spokeswoman said: "At approximately 6 p.m. this evening we were informed by various news organisations in Northern Ireland that they had received coded threats that there was a bomb at South Quay station, and at 7 p.m. a device exploded in that area.
The owner of a nearby wine bar described how the ceiling fell in and glass shattered. Ms Linda Holmes (39), proprietor of Trade Winds, said she was first alerted by police an hour before the explosion. They sealed off Marsh Wall, near her bar, but there was no order to evacuate.
"We were told it was a bomb scare. We thought it was a hoax because we were not told to evacuate," she said.
There were around 20 people in the bar at the time.
"When the bomb did go off everyone went on the floor. Glass and the ceiling fell on top of us and the radiators came away from the walls.
"But no one was hurt because our instinct was to act quickly and get on the floor.
"The police then told us to get out."
The Trade Winds landlord, Mr Steve Holmes (41), said one building separating the bar from the blast was reduced to a shell. "That was all that stood between us and the explosion. If it hadn't been there we could all have been killed." He said police first blocked off the road outside the bar one hour before the blast.
"We thought it was a hoax. It didn't seem to be a serious situation. When the bomb went off it was a deafening noise. All the windows came in and the ceiling fell down.
"Everyone just flung themselves on to the floor. It's amazing no one was injured."
A spokesman for the Fire Brigade said 20 pumps with 100 firefighters were dealing with the partial collapse of the buildings in Marsh Wall. "The area is not yet safe", he said late last night.
Office workers spoke of an enormous explosion which shook the area. An architect, Mr Giovanni Agnelli (30), was visiting a friend near South Quay station when the blast hit.
"We heard an almighty thud and all the windows shook. It shook the whole building. Doors were blown off their sliders and the walls shook.
"I opened the window backing on to the dock and looked out towards the station and I could see a huge pall of smoke billowing out towards the water.
"We got inside and as we did so we could hear a lot of falling glass.
"As we got inside a security guard came in and said we had to clear the building as soon as possible, because there had been a bomb and there might be another one."
Another eyewitness, Mr Bob Bassi, said windows of all the buildings around him shattered.
"All the windows are totally destroyed. The glass is gone front and back."
He said the house he was in "just shook" with the blast.
Just after 7.30 p.m., Mr Bassi reported that all the lights in surrounding buildings had gone out and the area was blacked out.
The Canary Wharf tower, Europe's tallest office building, contains the offices of several banks and national newspapers.
Ms Toni Heaton said she was relaxing at her home several miles away in Leytonstone, east London, when she heard "three loud tinny bangs, three waves of explosions.
"It was very, very loud. I wasn't frightened because I've heard five other bombs go off in London before.
"The dog flew off the bed. At first I thought it was coming from roadworks but when I rang 999 they told me it was a bomb."
People around Docklands and south London reported windows being blown in and damage from flying glass.
A security guard, Mr Kevin Grant, who works in the nearby Beaufort Court office block, said that minutes before the explosion police arrived and told him to evacuate the building immediately.
"I started going up the building to get people out and as I reached the fourth floor the bomb went off, and the force of the explosion threw me against the wall."
Despite bruising to a shoulder, he continued evacuating the block until everyone was out and then left himself.