manhattan manhole explosion
Firefighters are battling multiple manhole fires after an explosion early Friday morning in downtown Manhattan, at 12th Street and Broadway
A large explosion was heard in lower Manhattan early Friday morning, near the Union Square area.

According to firefighter scanner activity, the explosion was caused by a manhole blast that several manholes on fire.

The explosion occurred just after 7am, at the intersection of Broadway and East 12th Street - near the landmark bookstore, The Strand.

It's unclear if anyone was injured in the incident or what sparked the blast, but trucks for the city's gas provider, ConEdison, were on the scene.

The windows were blown out of The Strand bookstore and apartments above.

Jeff Ayers, manager for the Forbidden Planet bookstore next door, told Daily Mail.com:

'It was a transformer explosion. There was smoke billowing out of the corner.

'I have talked to a number of residents in the building and it woke them up. Some of the windows were shattered. The Strand windows have blown out.

'It doesn't seem Iike anyone got hurt,' he said.

12th Street was closed from 4th Avenue to Broadway while firefighters investigated the blast.

By 8:30am, there was still a lot of smoke at the site but it did not appear that there were any active flames anymore. Firefighters have reported some residual gas in the four buildings impacted by the blast.

The city's emergency management tweeted around 8:05 am to expect 'extensive traffic delays in the area' due to 'multiple manhole fires'.

Almost exactly two years ago, an apartment building just blocks away in the East Village was leveled by a gas explosion. Two people were killed in the ensuing fire.

Prosecutors have accused the building's owners of illegally tapping the gas lines in the building.

A year before that, there was yet another gas explosion uptown in East Harlem. Eight people were killed in that incident, which was blamed on improperly welded gas lines and a sewer issue that the city could have fixed.