VIDEO: New York City explosion captured by surveillance cameras

CHELSEA, Manhattan -- Surveillance video shows the explosion in Chelsea that injured dozens of people Saturday night.

The explosion went off at about 8:30 p.m. on West 23rd between 6th and 7th avenues.

The video shows the blast and then the aftermath with people running away.

The explosion was felt and heard for many blocks.

Another video that claims to be "leaked video" is making rounds on social media. It shows a wider shot outside:

Watch Kristin Thorne's report on the surveillance video here:

Kristin Thorne reports live from Chelsea.