A massive explosion has leveled two apartment buildings in New York City, killing at least two women.

Fire officials said more than 20 others were hurt, two of them with life-threatening injuries. More than a dozen people are still missing.

The National Transportation Safety Board said it was sending a team of experts to New York City to investigate the accident.

A utility company said a resident in a nearby building reported smelling gas shortly before the blast. Police set up barricades and handed out masks to residents and onlookers to protect them from the thick, acrid smoke that shrouded the area. Train services were suspended to and from Grand Central on all three train lines while employees removed debris from the tracks.

The National Transportation Safety Board said it was sending a team of experts to New York City to investigate the accident.