NEW YORK: At least two persons (both women) were killed and up to 18 injured when two five-storey buildings in East Harlem part of New York City collapsed after a powerful explosion.

The explosion which sparked fears of terrorist attacks was possibly caused by gas leaks, the police department said.

The Mayor of New York city Bll De Blasio told a press conference “from what we know now its was due to gas leak'” but he quickly added it was based on preliminary investigations. He said up to 18 people were injured and a number of others were missing.

Metro-North Railroad service in and out of Grand Central Terminal was suspended with debris from the buildings thrown onto the elevated train tracks on 116th Street and Park Avenue.

Commuters on a southbound Metro-North train that had just passed 116th Street said that the train shook violently.

Con Edison, the New York utilities company, had been called to the area to check a possible gas leak just before the explosion around 9am news reports said.

"For weeks we've been smelling gas,” Ashley Rivera, 21, told the Daily News newspaper. “We saw people flying out of the window. ... Those are my neighbours."

Eoin Hayes, 26, said the explosion shook his apartment building almost 10 blocks away.

"I was in my bedroom and the explosion went off, it kind of shook the whole building,” Hayes told the Associated Press. “You could feel the vibrations going through the building. I ran to the window and saw the fire and the smoke going up and the sirens start."