NEW YORK (CBSNewYork/AP) — Frantic families have been anxiously waiting to make sure their loved ones were not in two buildings that collapsed in East Harlem.

An explosion Wednesday morning leveled the structures, killing two people and injuring dozens more.

The Fire Department said more than a dozen people are still missing.

PHOTOS: Harlem Explosion | Watch Live

Mayor Bill de Blasio said some of those unaccounted for may have fled to safety.

“I emphasize that those who are missing could well be safe in another location and just not contacted yet or reachable yet,” de Blasio said. “There is going to be a thorough search to try and find or locate each individual.”

One woman, Lenore Lovejoy, was looking for word on her cousin and another relative.

Another woman begged for help as she tried to find out whether the building where her daughter had just moved into was among the collapsed structures.

The two collapsed buildings, 1644 and 1646 Park Avenue, were both five-stories. One of the buildings had a piano repair shop with apartments above. The second building housed a church.

Carmen Vargas-Rosa, who owns the church, said four of her tenants who live above the church are unaccounted for.

“One of them was off from work so most likely she was in the building,” Vargas-Rosa said. “We have a mother who has a sick son, so unless they were at an appointment in the hospital, they may have been in the explosion and then we have a young man and his wife who go to school late so they may have been sleeping and we can’t reach them.”

De Blasio said a hotline was being set up for families looking for loved ones. In the meantime, he said worried relatives can call 311.

The White House issued a statement offering “thoughts and prayers” and commending first responders.

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