One person has died in hospital after an underground steam pipe explosion tore through a New York street.
Hundreds fled when a towering geyser of steam and rubble burst into the air near Grand Central Terminal during Wednesday evening's rush hour. Several people were injured, at least four of them seriously.
New York Police Department spokesman Paul Browne said the explosion was not terrorism.
New York Mayor Michael Bloomberg said at a news conference at the scene of the blast: "There is no reason to believe whatsoever that this is anything other than a failure of our infrastructure."
The plume of steam and mud generated a tremendous roar. The initial burst rose higher than the nearby 77-storey Chrysler Building, one of Manhattan's tallest. The air near the site was filled with debris.
Heiko Thieme, an investment banker, had mud splattered on his face, trousers and shoes. He said the explosion was like a volcano.
"Everybody was a bit confused, everybody obviously thought of 9/11," he said, referring to the September 11, 2001 terror attacks that demolished the World Trade Centre.
Thousands of commuters evacuated the Grand Central train terminal, some at a run, after workers yelled for people to get out of the building. A small school bus was abandoned just feet from the spot where the jet of steam spewed from the ground.
One eyewitness said she thought the rumble from the explosion was thunder: "I looked out of the window and I saw these huge chunks that I thought were hail. We panicked, I think everyone thought the worst. Thank God it wasn't. It was like a cattle drive going down the stairs, with everyone pushing. I almost fell."
Streets were closed for several blocks in all directions. The subway service in the area was suspended.
