NEW YORK (CBSNewYork/AP) — Two manholes and two gratings exploded near Penn Station in Midtown Manhattan on Wednesday, snarling traffic in the area.

The blasts occurred at the corner of Eighth Avenue and West 35th Street at around 10:16 a.m. They produced flames that quickly dissipated. But smoke and an acrid odor hung over the busy commercial area.

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Firefighters told CBS2’s Elise Finch a fire broke out underground, leading to the explosion.

Witnesses said at first they weren’t sure what was happening, Finch reported.

People in the area said there were some very tense moments. There was fire, smoke and people scrambling, they said.

“I thought it was thunder actually,” said Gabriel Sharpe of Brooklyn.

“I heard a loud explosion, and I felt all this hot air hit me,” Thomas McDonough said. “And it knocked me back, and I almost went down. I saw the flames flying in the air. I then panic, and I started to go out across the street. And I was waiting a minute and I was going to go on the other side, and the other one went up, and that one really hit me in the face, and the flames went up. Next thing I know, a police officer had me by the back and was dragging me across the street, saying, ‘I’ve got to get you out of here.'”

“People were running, trying to get out of the area because they didn’t actually know what it was, and then we realized that it was a manhole cover,” said witness Elle Kitchings. “The second manhole cover was so powerful it split the manhole in half.”

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Police evacuated The New Yorker hotel and the studios of Al Jazeera America.

“To be honest with you — a bomb. That’s the first thing that came to my mind a lot of other people were thinking the same way,” said Jonathan Muscarella  who works at 1 Penn Plaza.

A firefighter on the scene told Finch that the FDNY had to check with Con Edison to make sure it was OK to put water on the fire to put it out. Once that was done, firefighters were sent into nearby buildings to check carbon monoxide levels.

Con Ed said it owns two the manholes, and the others belong to Cablevision and Verizon.

Police blocked off Eighth Avenue between 34th and 36th streets for a few hours.

There were no serious injuries or power outages as a result of the explosion.

There is still no word on what caused the explosions.

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