NEW YORK — A gas leak was responsible for a major explosion that destroyed two buildings in Manhattan on Wednesday, killing two people and injuring 18 others, New York Mayor Bill de Blasio said.

“Today at approximately 9:30 am, there was a major explosion that destroyed two buildings. The explosion was based on a gas leak,” de Blasio told reporters at the scene.

A number of individuals are still missing, de Blasio confirmed, sparking fears that the death toll could yet rise further, but he cautioned that some of those missing could simply be safe elsewhere and out of contact.

“This is a tragedy of the worst kind, because there was no indication in time to save people. We know we have lost two people already. We know at this moment, preliminarily, 18 are injured,” the mayor said.

“There is a tremendous amount of anxiety, but suffice it to say that every effort is being expended to locate each and every one of these (missing) individuals,” he said.

De Blasio said there was a “very heavy impact” on buildings that surrounded the two that collapsed, and that 250 firefighters were attempting to extinguish a heavy blaze that broke out.

New York City Public Advocate Bill de Blasio (photo credit: Courtesy BilldeBlasio.com)

New York mayor Bill de Blasio (photo credit: Courtesy BilldeBlasio.com)

All the details he had were preliminary, the mayor emphasized, and simply the “best information we have at this moment.”

“From what we know now, the only indication of danger came about 15 minutes earlier when a gas leak was reported to (energy company) Con Edison,” de Blasio told reporters.