NEW YORK, March 12 (Xinhua) -- At least two people were killed and 18 others injured when two residential buildings collapsed in an explosion in New York's East Harlem neighborhood on Wednesday, authorities said.
The blast struck a building at 116th Street and Park Avenue in Upper Manhattan at about 9:30 a.m. local time (1330 GMT), blowing out windows in surrounding buildings and sending debris crashing down onto nearby streets.
Two residential buildings next door to each other collapsed in the incident and one of the five-story building was essentially gone from the blast.
New York Mayor Bill de Blasio said that at least two people were killed and 18 others injured in the collapse.
"The explosion was based on a gas leak. The impact affected buildings around the two that were destroyed, very heavy impacts on the surrounding buildings. A heavy fire has ensued as well," he told reporters at the scene shortly after noon.
"A number" of people were still missing after the explosion and about 250 firefighters were battling to extinguish the heavy blaze, the mayor said.
"There will be a search through the rubbles of the building as soon as the fire is put out looking for those who are missing," de Blasio said.
Smoke and ashes from the explosion can still be seen pouring into the neighborhood.
Gregory Garcia, who was just a block away from the scene before the explosion, told Xinhua that he was shocked by a huge explosion. Everyone was running in panic without knowing what had happened, he said.
The two collapsed five-story buildings had a piano store and a Spanish Christian Church on the ground floor and apartments on the upper, Garcia said.
Local utility company Con Edison said it received a call from a resident of an adjacent building reporting that he smelled gas inside his apartment, but he thought the smell could be coming from outside.
The company said it sent two crews to the scene after the call, but they arrived just after the explosion.
Further investigation into the cause was still underway.