DHAKA: Three people have died and nine are missing after a gas leak sparked an explosion which leveled two buildings in New York City, authorities say.

Scores of others have been injured in the incident, which sent smoke billowing into the city sky, BBC reported.

Rescue crews began searching the debris on Wednesday evening for victims after the fire was finally put out.

Train services to and from Grand Central Terminal have been restored after a complete halt earlier.

Missing people

New York City Mayor Bill de Blasio said in a news conference from the scene that the gas leak had been reported to the utility company 15 minutes before the blast on Wednesday morning.

"We heard `boom` and all the windows broke down"

Bill de Blasio said the "major explosion" had destroyed two buildings and heavily damaged other structures.

The mayor`s office confirmed to the Associated Press news agency that nine people were still missing by early Wednesday evening.

As night fell, rescue crews were finally able to search for victims in the debris after the fire raged for most of the day.

Heavy equipment, including a bulldozer, helped clear the remnants of two multi-storey buildings. Thermal imaging cameras were brought in to identify bodies or pockets of fire inside the mountain of debris.

The New York fire department said 22 people had been hurt, but a tally of local hospitals by ABC News found that 64 had been admitted with injuries as a result of the incident.

That figure included seven children, one of whom was in a critical condition.

The area is engulfed in thick choking smoke, says the BBC`s Nick Bryant at the scene

The utility company, Con Edison, says a resident in a nearby building reported smelling gas shortly before the explosion.

Streets and pavements around the site were littered with broken glass from shattered windows.

BDST: 1101 HRS, MAR 12, 2014