A gas tank truck explosion collapsed large parts of a Mexico City children's hospital on Thursday morning, reportedly leaving at least seven people dead and dozens more injured or believed to be trapped, civil protection officials said.

The natural gas explosion occurred outside a maternity and children's hospital of Cuajimalpa in Mexico City, resulting in the collapse of 30 to 40 percent of the hospital building, according to Mexico City Mayor Miguel Angel Mancera. About 54 people have reportedly been injured, including 22 children and 32 adults, according to the Mexican newspaper El Universal.

While 37 people, including nine infants, have been transported to nearby hospitals for treatment, an unknown number of others are likely still buried in the rubble, said Fausto Lugo, the city's civil defense director. The Mexican Army has been deployed to the site for help, who are searching for victims of the blast.

"According to the report I have of the injured, the majority of the injuries are from glass, the explosion caused a variety of glass to hit and cut people," Mancera said in an interview according to Mexico's Reforma newspaper.

On Thursday morning, a truck was supplying gas to the hospital when a hose unexpectedly burst and resulted in a leak, which eventually caused the explosion, Mancera said, adding that the explosion sent a column of smoke billowing over the area in western Mexico City, with the heaviest damage being near the hospital's loading dock.

Although injured victims are being transferred to other hospitals, the area has insufficient ambulances, Borough chief Adrian Rubalcava said. "The most worrisome is the collapse of a large part of the hospital."

According to photos from the scene, the gas truck belonged to Gas Express Nieto, a natural gas provider among the four biggest gas distributors in Mexico. The company has made no immediate comments on the explosion, CNN reported.

Currently, the hospital seems to be on the verge of collapsing, Mancera said.

The Cuajimalpa Maternal Hospital, located on the southwest outskirts of Mexico City, was founded in 1993 and is part of the city's government health system, Fox News reported.