LONDON, England (CNN) -- One of the passengers trapped in a London Underground train said he and shocked, hysterical, fearful commuters "were all trapped like sardines waiting to die."
Lawyer Angelo Power described to CNN a high-pitched atmosphere of "pandemonium."
"I honestly thought I was going to die," the disheveled man said, adding he was "grateful to be alive."
He said seconds after leaving Kings Cross station, there was a "large bang," and people were "physically ejected" from their seats.
There were "flashes of light on the side of the tube carriage."
Smoke "immediately billowed" into the carriage, he said, and "people started to scream because there was a burning smell."
"Everyone ... thought they were going to die. People started saying prayers, praying to God. Panicking. Breaking the carriage windows with bare hands. Anything to get oxygen into the carriage."
The scene went black, people passed out and others became "very agitated." And, he said, the screaming got worse.
"There was no communication from any drivers. Everyone was in pitch black, and then the emergency lights came on and more and more smoke started coming into the carriage.
"And we were there for something like 20 to 30 minutes, during which the smoke intensified, the screaming intensified, and the hysteria, and that's what it was, became almost ... pandemonium."
Eventually, somebody said someone at the back carriage had managed to force open a door, and smoke was seen coming down the tunnel, said Power, who said he was in the second to the back carriage.
"But they wouldn't get out because they thought they were going to be electrocuted by the live train lines.
"Then smoke was coming down the tunnel. Nobody would go out of that exit. No one would go out of the other exit because, as I understand it, there's a bomb in the middle of the carriage."
He said that "we were all trapped like sardines waiting to die. And I honestly thought my time was up as did everyone else."
In 30 minutes or so, he said, people overcame their fear and made their way out of the carriage in a controlled manner. People were injured and windows were smashed, he said.
He said he saw people's belongings scattered all over the place.
"There were no emergency people on hand to escort anyone off the train," except for two officers, he said.
There was no medical operation at first, he said, noting that everyone initially thought a technical failure was its source.
"It's just mass communication failure."
He also wanted to know why the train proceeded from another stop when authorities knew or must have known these things were happening.
"It's almost negligent."
He said in light of the Madrid bombings not long ago, he is "at a loss to say why this was."
"In hindsight, which is always a great factor, that things could have been done a lot better perhaps."
He said he takes pity whoever has "perpetuated such a wicked act."Bus explosion
Raj Mattoo, 35, was standing on a corner when there was an explosion on a bus at nearby Tavistock Place.
He told the UK's Press Association: "The explosion seemed to be at the back of the bus. The roof flew off and went up about 10 meters (11 yards). It then floated back down.
"A parking attendant said he thought a piece of human flesh had landed on his arm," he said.
Belinda Seabrook told PA that she was on the bus in front when she heard an incredible bang. "I turned round, and half the double decker bus was in the air," she said.
Abigail Milner, of South Africa, said she'd just walked across the road when the bus exploded.
"...I saw large pieces of metal flying, and I just turned and covered myself and ran to get away from anything that might harm me," she said.
"The next time I saw it was when they brought us out of hotel once they got casualties away. It just looked like a mangled piece of metal."Edgware road
Marcin Stefanski was in the carriage next to the one that exploded at Edgware Road station. He said he saw bodies piled in the blast-strewn wreckage.
He told PA: "I just experienced a huge explosion and the glass hitting me in my back. People started screaming around me, there was glass everywhere, we couldn't breathe, there was no way to get off the train."
Stefanski, a 24-year-old student who recently moved to the UK from Poland, was among many passengers covered in soot. He coughed repeatedly as he relived his experience.
"I was in the front of the first carriage and there was a huge, massive hole in the carriage.
"As I went past the second carriage I could just see the bodies lying all over the floor."
Lisa Levine, an American nurse visiting London, and travelling on a train headed to Edgware Road station, said she saw several corpses after the bomb went off.
Asked what she thought of then, she replied, "9/11."
She said, "It seemed like forever" before the paramedics came -- maybe 20 minutes -- and there was no way to get into the car behind hers, where the screaming was coming from.Liverpool Street
Andrew Robinson e-mailed CNN with the following account:
"I was on the last carriage on the train that exploded just outside Aldgate. The train juddered to a halt and all the lights went out; a load of dust from the seats flew up and we were coughing. There was a strange burning smell, almost like hot metal or an electrical smell. At first we thought the train had derailed and started to joke about it but somewhere in front someone was screaming. Still, we thought they were just claustrophobic or something. There was no panic or real fear, just irritation that we would be late for work. At this point we didn't realise what had happened.
"Twenty minutes after stopping we were led out of the back and told to walk forwards past the length of the train to the front, where the nearest platform was. Two carriages in front of mine we saw a big hole in the side and three people lying on the tracks covered in blood. At least two were probably dead. Bits of train littered the ground. It was obvious then that it had been a bomb and I started shaking. One woman started crying.
"The carriage that was hit was obviously badly damaged, but in comparison to the Madrid trains the hole was not as big. We were lucky that the tunnel we were in was two trains wide, so the blast was not contained in such a small area. We only had a short flight of stairs to climb and came out into the open air to see the emergency services sealing off the area. I knew then that something big had happened.
"It has been a great comfort to hear message of support from the people of New York and Madrid. There is a strange sense of international solidarity which is a great help. Last night I walked 4 miles across London thinking of the images of New Yorkers walking away from the twin towers - because there was nothing else they could do.
"The police have told us to stay at home on Friday, so I will. But on Monday morning I will get on the train, get on the underground and go about my normal business -- because I will not let them change my way of life."
Sarah Reid, 23, a student doing work experience, was on the carriage next door to the one which was struck by an explosion near Liverpool Street station. She told PA that she was led out and down the track after seeing a carriage ripped apart with the roof blown off.
"I think some people may have died," she told PA.
The blast had pulled some people's clothes off.
She said the explosion happened at 8.50 a.m. but she was not able to get off the carriage until 9.30 a.m.
Reid said an announcement came on but cut off after saying: "Hello."
"There was really hard banging from the carriage next door to us," she said, describing events immediately after the blast.
Describing being led away from the scene, she said: "A carriage was split in two, all jagged, and without a roof, just open.
"I saw bodies, I think."